Cineromycin B isolated from Streptomyces cinerochromogenes inhibits adipocyte differentiation of 3T3-L1 cells via Krüppel-like factors 2 and 3.

PubMed

Matsuo, Hirotaka; Kondo, Yoshiyuki; Kawasaki, Takashi; Imamura, Nobutaka

2015-08-15

3T3-L1 cells are preadipocytes and often used as a model for cellular differentiation to adipocytes; however, the mechanism of this differentiation is not completely understood even in these model cells. In this study, we sought to identify a unique anti-adipogenesis agent from microorganisms and to examine its mechanism of action to gain knowledge and create a tool and/or seed compound for anti-obesity drug discovery research. Screening for anti-adipogenesis agents from microorganisms was performed using a 3T3-L1 cell differentiation system, and an active compound was isolated. The inhibitory mechanism of the compound was investigated by measuring the expression of key regulators using quantitative real-time PCR and Western blot analysis. The compound with anti-adipogenic activity in 3T3-L1 cells was identified as cineromycin B. Cineromycin B at 50 μg/mL suppressed intracellular lipid accumulation and the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer binding protein alpha (C/EBPα), which are master regulators of adipocyte differentiation. Further investigations showed that cineromycin B increased significantly the mRNA expression of two negative regulators of adipocyte differentiation, Krüppel-like factor (KLF) 2 and KLF3, at an early stage of the differentiation. The results of siRNA transfection experiments indicated that cineromycin B is a unique adipocyte differentiation inhibitor, acting mainly via upregulation of KLF2 and KLF3, and these KLFs may play a role in the early stage of differentiation. Cineromycin B inhibited adipocyte differentiation in 3T3-L1 cells mainly via upregulation of KLF2 and KLF3 mRNA expression at an early stage of the differentiation. Copyright © 2015. Published by Elsevier Inc.

Diabetic human adipose tissue-derived mesenchymal stem cells fail to differentiate in functional adipocytes.

PubMed

Barbagallo, Ignazio; Li Volti, Giovanni; Galvano, Fabio; Tettamanti, Guido; Pluchinotta, Francesca R; Bergante, Sonia; Vanella, Luca

2017-05-01

Adipose tissue dysfunction represents a hallmark of diabetic patients and is a consequence of the altered homeostasis of this tissue. Mesenchymal stem cells (MSCs) and their differentiation into adipocytes contribute significantly in maintaining the mass and function of adult adipose tissue. The aim of this study was to evaluate the differentiation of MSCs from patients suffering type 2 diabetes (dASC) and how such process results in hyperplasia or rather a stop of adipocyte turnover resulting in hypertrophy of mature adipocytes. Our results showed that gene profile of all adipogenic markers is not expressed in diabetic cells after differentiation indicating that diabetic cells fail to differentiate into adipocytes. Interestingly, delta like 1, peroxisome proliferator-activated receptor alpha, and interleukin 1β were upregulated whereas Sirtuin 1 and insulin receptor substrate 1 gene expression were found downregulated in dASC compared to cells obtained from healthy subjects. Taken together our data indicate that dASC lose their ability to differentiate into mature and functional adipocytes. In conclusion, our in vitro study is the first to suggest that diabetic patients might develop obesity through a hypertrophy of existing mature adipocytes due to failure turnover of adipose tissue. Impact statement In the present manuscript, we evaluated the differentiative potential of mesenchymal stem cells (MSCs) in adipocytes obtained from healthy and diabetic patients. This finding could be of great potential interest for the field of obesity in order to exploit such results to further understand the pathophysiological processes underlying metabolic syndrome. In particular, inflammation in diabetic patients causes a dysfunction in MSCs differentiation and a decrease in adipocytes turnover leading to insulin resistance.

Soluble soy protein peptic hydrolysate stimulates adipocyte differentiation in 3T3-L1 cells.

PubMed

Goto, Tsuyoshi; Mori, Ayaka; Nagaoka, Satoshi

2013-08-01

The molecular mechanisms underlying the potential health benefit effects of soybean proteins on obesity-associated metabolic disorders have not been fully clarified. In this study, we investigated the effects of soluble soybean protein peptic hydrolysate (SPH) on adipocyte differentiation by using 3T3-L1 murine preadipocytes. The addition of SPH increased lipid accumulation during adipocyte differentiation. SPH increased the mRNA expression levels of an adipogenic marker gene and decreased that of a preadipocyte marker gene, suggesting that SPH promotes adipocyte differentiation. SPH induced antidiabetic and antiatherogenic adiponectin mRNA expression and secretion. Moreover, SPH increased the mRNA expression levels of insulin-responsive glucose transporter 4 and insulin-stimulated glucose uptake. The expression levels of peroxisome proliferator-activated receptor γ (PPARγ), a key regulator of adipocyte differentiation, during adipocyte differentiation were up-regulated in 3T3-L1 cells treated with SPH, and lipid accumulation during adipocyte differentiation induced by SPH was inhibited in the presence of a PPARγ antagonist. However, SPH did not exhibit PPARγ ligand activity. These findings indicate that SPH stimulates adipocyte differentiation, at least in part, via the up-regulation of PPARγ expression levels. These effects of SPH might be important for the health benefit effects of soybean proteins on obesity-associated metabolic disorders. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Clozapine modifies the differentiation program of human adipocytes inducing browning.

PubMed

Kristóf, E; Doan-Xuan, Q-M; Sárvári, A K; Klusóczki, Á; Fischer-Posovszky, P; Wabitsch, M; Bacso, Z; Bai, P; Balajthy, Z; Fésüs, L

2016-11-29

Administration of second-generation antipsychotic drugs (SGAs) often leads to weight gain and consequent cardio-metabolic side effects. We observed that clozapine but not six other antipsychotic drugs reprogrammed the gene expression pattern of differentiating human adipocytes ex vivo, leading to an elevated expression of the browning marker gene UCP1, more and smaller lipid droplets and more mitochondrial DNA than in the untreated white adipocytes. Laser scanning cytometry showed that up to 40% of the differentiating single primary and Simpson-Golabi-Behmel syndrome (SGBS) adipocytes had the characteristic morphological features of browning cells. Furthermore, clozapine significantly upregulated ELOVL3, CIDEA, CYC1, PGC1A and TBX1 genes but not ZIC1 suggesting induction of the beige-like and not the classical brown phenotype. When we tested whether browning induced by clozapine can be explained by its known pharmacological effect of antagonizing serotonin (5HT) receptors, it was found that browning cells expressed 5HT receptors 2A, 1D, 7 and the upregulation of browning markers was diminished in the presence of exogenous 5HT. Undifferentiated progenitors or completely differentiated beige or white adipocytes did not respond to clozapine administration. The clozapine-induced beige cells displayed increased basal and oligomycin-inhibited (proton leak) oxygen consumption, but these cells showed a lower response to cAMP stimulus as compared with control beige adipocytes indicating that they are less capable to respond to natural thermogenic anti-obesity cues. Our data altogether suggest that novel pharmacological stimulation of these masked beige adipocytes can be a future therapeutic target for the treatment of SGA-induced weight gain.

Clozapine modifies the differentiation program of human adipocytes inducing browning

PubMed Central

Kristóf, E; Doan-Xuan, Q-M; Sárvári, A K; Klusóczki, Á; Fischer-Posovszky, P; Wabitsch, M; Bacso, Z; Bai, P; Balajthy, Z; Fésüs, L

2016-01-01

Administration of second-generation antipsychotic drugs (SGAs) often leads to weight gain and consequent cardio-metabolic side effects. We observed that clozapine but not six other antipsychotic drugs reprogrammed the gene expression pattern of differentiating human adipocytes ex vivo, leading to an elevated expression of the browning marker gene UCP1, more and smaller lipid droplets and more mitochondrial DNA than in the untreated white adipocytes. Laser scanning cytometry showed that up to 40% of the differentiating single primary and Simpson–Golabi–Behmel syndrome (SGBS) adipocytes had the characteristic morphological features of browning cells. Furthermore, clozapine significantly upregulated ELOVL3, CIDEA, CYC1, PGC1A and TBX1 genes but not ZIC1 suggesting induction of the beige-like and not the classical brown phenotype. When we tested whether browning induced by clozapine can be explained by its known pharmacological effect of antagonizing serotonin (5HT) receptors, it was found that browning cells expressed 5HT receptors 2A, 1D, 7 and the upregulation of browning markers was diminished in the presence of exogenous 5HT. Undifferentiated progenitors or completely differentiated beige or white adipocytes did not respond to clozapine administration. The clozapine-induced beige cells displayed increased basal and oligomycin-inhibited (proton leak) oxygen consumption, but these cells showed a lower response to cAMP stimulus as compared with control beige adipocytes indicating that they are less capable to respond to natural thermogenic anti-obesity cues. Our data altogether suggest that novel pharmacological stimulation of these masked beige adipocytes can be a future therapeutic target for the treatment of SGA-induced weight gain. PMID:27898069

Ursodeoxycholic Acid but Not Tauroursodeoxycholic Acid Inhibits Proliferation and Differentiation of Human Subcutaneous Adipocytes

PubMed Central

Mališová, Lucia; Kováčová, Zuzana; Koc, Michal; Kračmerová, Jana; Štich, Vladimír; Rossmeislová, Lenka

2013-01-01

Stress of endoplasmic reticulum (ERS) is one of the molecular triggers of adipocyte dysfunction and chronic low inflammation accompanying obesity. ERS can be alleviated by chemical chaperones from the family of bile acids (BAs). Thus, two BAs currently used to treat cholestasis, ursodeoxycholic and tauroursodeoxycholic acid (UDCA and TUDCA), could potentially lessen adverse metabolic effects of obesity. Nevertheless, BAs effects on human adipose cells are mostly unknown. They could regulate gene expression through pathways different from their chaperone function, namely through activation of farnesoid X receptor (FXR) and TGR5, G-coupled receptor. Therefore, this study aimed to analyze effects of UDCA and TUDCA on human preadipocytes and differentiated adipocytes derived from paired samples of two distinct subcutaneous adipose tissue depots, abdominal and gluteal. While TUDCA did not alter proliferation of cells from either depot, UDCA exerted strong anti-proliferative effect. In differentiated adipocytes, acute exposition to neither TUDCA nor UDCA was able to reduce effect of ERS stressor tunicamycin. However, exposure of cells to UDCA during whole differentiation process decreased expression of ERS markers. At the same time however, UDCA profoundly inhibited adipogenic conversion of cells. UDCA abolished expression of PPARγ and lipogenic enzymes already in the early phases of adipogenesis. This anti-adipogenic effect of UDCA was not dependent on FXR or TGR5 activation, but could be related to ability of UDCA to sustain the activation of ERK1/2 previously linked with PPARγ inactivation. Finally, neither BAs did lower expression of chemokines inducible by TLR4 pathway, when UDCA enhanced their expression in gluteal adipocytes. Therefore while TUDCA has neutral effect on human preadipocytes and adipocytes, the therapeutic use of UDCA different from treating cholestatic diseases should be considered with caution because UDCA alters functions of human adipose cells

Proliferation and differentiation of brown adipocytes from interstitial cells during cold acclimation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bukowiecki, L.J.; Geloeen, A.; Collet, A.J.

1986-06-01

The mechanisms of brown adipocyte proliferation and differentiation during cold acclimation (and/or adaptation to hyperphagia) have been studied by quantitative photonic radioautography. (/sup 3/H)thymidine was injected to warm-acclimated (25/sup 0/C) rats and to animals exposed to 5/sup 0/C for 2 days. Samples of interscapular brown adipose tissue were collected for quantitative analysis of mitotic frequencies at various periods of time (4 h-15 days) after the injection of (/sup 3/H)thymidine, the rats being maintained at the temperatures to which they were initially exposed. It was found that cold exposure for 2 days markedly enhanced mitotic activity in endothelial cells, interstitial cells,more » and brown preadipocytes rather than in fully differentiated brown adipocytes. The total tissue labeling index (percent of labeled nuclei) increased approx.70 times over control values. The authors now report that cellular labeling progressively increased in mature brown adipocytes during cold acclimation, whereas it correspondingly decreased in interstitial cells and brown preadipocytes. This indicates that the sequence of events for cellular differentiation is interstitial cells ..-->.. brown preadipocytes ..-->.. mature brown adipocytes. Remarkable, labeling frequency did not change in endothelial cells during cold acclimation demonstrating that these cells cannot be considered as progenitors of brown adipocytes. It is suggested that brown adipocyte proliferation and differentiation from interstitial cells represent the fundamental phenomena explaining the enhanced capacity of cold-acclimated and/or hyperphagic rats to respond calorigenically to catecholamines.« less

Tyrphostin AG17 inhibits adipocyte differentiation in vivo and in vitro.

PubMed

Camacho, Alberto; Segoviano-Ramírez, Juan Carlos; Sánchez-Garcia, Adriana; de Jesus Herrera-de la Rosa, Jose; García-Juarez, Jaime; Hernandez-Puente, Carlos Alberto; Calvo-Anguiano, Geovana; Maltos-Uro, Sergio Rodolfo; Olguin, Alejandra; Gojon-Romanillos, Gabriel; Gojon-Zorrilla, Gabriel; Ortiz-Lopez, Rocio

2018-05-29

Excessive subcutaneous adiposity in obesity is associated to positive white adipocyte tissue (WAT) differentiation (adipogenesis) and WAT expandability. Here, we hypothesized that supplementation with the insulin inhibitor and mitochondrial uncoupler, Tyrphostin (T-AG17), in vitro and in vivo inhibits adipogenesis and adipocyte hypertrophy. We used a 3T3-L1 proadipocyte cell line to identify the potential effect of T-AG17 on adipocyte differentiation and fat accumulation in vitro. We evaluated the safety of T-AG17 and its effects on physiological and molecular metabolic parameters including hormonal profile, glucose levels, adipogenesis and adipocyte hypertrophy in a diet-induced obesity model using C57BL/6 mice. We found that T-AG17 is effective in preventing adipogenesis and lipid synthesis in the 3T3-L1 cell line, as evidenced by a significant decrease in oil red staining (p < 0.05). In obese C57BL/6 mice, oral administration of T-AG17 (0.175 mg/kg for 2 weeks) lead to decreased fat accumulation and WAT hypertrophy. Further, T-AG17 induced adipocyte apoptosis by activating caspase-3. In the hepatocytes of obese mice, T-AG17 promoted an increase in the size of lipid inclusions, which was accompanied by glycogen accumulation. T-AG17 did not alter serum biochemistry, including glucose, insulin, leptin, free fatty acids, creatinine, and aspartate aminotransferase. T-AG17 promotes adipocyte apoptosis in vivo and is an effective modulator of adipocyte differentiation and WAT hypertrophy in vitro and in vivo. Therefore, T-AG17 may be useful as a pharmacological obesity treatment.

Small Molecule-Induced Complement Factor D (Adipsin) Promotes Lipid Accumulation and Adipocyte Differentiation

PubMed Central

Jang, Byung-Hyun; Chang, Seo-Hyuk; Yun, Ui Jeong; Park, Ki-Moon; Waki, Hironori; Li, Dean Y.; Tontonoz, Peter; Park, Kye Won

2016-01-01

Adipocytes are differentiated by various transcriptional cascades integrated on the master regulator, Pparγ. To discover new genes involved in adipocyte differentiation, preadipocytes were treated with three newly identified pro-adipogenic small molecules and GW7845 (a Pparγ agonist) for 24 hours and transcriptional profiling was analyzed. Four genes, Peroxisome proliferator-activated receptor γ (Pparγ), human complement factor D homolog (Cfd), Chemokine (C-C motif) ligand 9 (Ccl9), and GIPC PDZ Domain Containing Family Member 2 (Gipc2) were induced by at least two different small molecules but not by GW7845. Cfd and Ccl9 expressions were specific to adipocytes and they were altered in obese mice. Small hairpin RNA (shRNA) mediated knockdown of Cfd in preadipocytes inhibited lipid accumulation and expression of adipocyte markers during adipocyte differentiation. Overexpression of Cfd promoted adipocyte differentiation, increased C3a production, and led to induction of C3a receptor (C3aR) target gene expression. Similarly, treatments with C3a or C3aR agonist (C4494) also promoted adipogenesis. C3aR knockdown suppressed adipogenesis and impaired the pro-adipogenic effects of Cfd, further suggesting the necessity for C3aR signaling in Cfd-mediated pro-adipogenic axis. Together, these data show the action of Cfd in adipogenesis and underscore the application of small molecules to identify genes in adipocytes. PMID:27611793

ATF3 represses PPARγ expression and inhibits adipocyte differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jang, Min-Kyung; Jung, Myeong Ho, E-mail: jung0603@pusan.ac.kr

Highlights: • ATF3 decrease the expression of PPARγ and its target gene in 3T3-L1 adipocytes. • ATF3 represses the promoter activity of PPARγ2 gene. • ATF/CRE (−1537/−1530) is critical for ATF3-mediated downregulation of PPARγ. • ATF3 binds to the promoter region containing the ATF/CRE. • ER stress inhibits adipocyte differentiation through downregulation of PPARγ by ATF3. - Abstract: Activating transcription factor 3 (ATF3) is a stress-adaptive transcription factor that mediates cellular stress response signaling. We previously reported that ATF3 represses CCAAT/enhancer binding protein α (C/EBPα) expression and inhibits 3T3-L1 adipocyte differentiation. In this study, we explored potential role of ATF3more » in negatively regulating peroxisome proliferator activated receptor-γ (PPARγ). ATF3 decreased the expression of PPARγ and its target gene in 3T3-L1 adipocytes. ATF3 also repressed the activity of −2.6 Kb promoter of mouse PPARγ2. Overexpression of PPARγ significantly prevented the ATF3-mediated inhibition of 3T3-L1 differentiation. Transfection studies with 5′ deleted-reporters showed that ATF3 repressed the activity of −2037 bp promoter, whereas it did not affect the activity of −1458 bp promoter, suggesting that ATF3 responsive element is located between the −2037 and −1458. An electrophoretic mobility shift assay and chromatin immunoprecipitation assay demonstrated that ATF3 binds to ATF/CRE site (5′-TGACGTTT-3′) between −1537 and −1530. Mutation of the ATF/CRE site abrogated ATF3-mediated transrepression of the PPARγ2 promoter. Treatment with thapsigargin, endoplasmic reticulum (ER) stress inducer, increased ATF3 expression, whereas it decreased PPARγ expression. ATF3 knockdown significantly blocked the thapsigargin-mediated downregulation of PPARγ expression. Furthermore, overexpression of PPARγ prevented inhibition of 3T3-L1 differentiation by thapsigargin. Collectively, these results suggest that ATF3

PPARγ ligand production is tightly linked to clonal expansion during initiation of adipocyte differentiation[S

PubMed Central

Hallenborg, Philip; Petersen, Rasmus Koefoed; Feddersen, Søren; Sundekilde, Ulrik; Hansen, Jacob B.; Blagoev, Blagoy; Madsen, Lise; Kristiansen, Karsten

2014-01-01

Adipocyte differentiation is orchestrated by the ligand-activated nuclear receptor PPARγ. Endogenous ligands comprise oxidized derivatives of arachidonic acid and structurally similar PUFAs. Although expression of PPARγ peaks in mature adipocytes, ligands are produced primarily at the onset of differentiation. Concomitant with agonist production, murine fibroblasts undergo two rounds of mitosis referred to as mitotic clonal expansion. Here we show that mouse embryonic fibroblasts deficient in either of two cell cycle inhibitors, the transcription factor p53 or its target gene encoding the cyclin-dependent kinase inhibitor p21, exhibit increased adipogenic potential. The antiadipogenic effect of p53 relied on its transcriptional activity and p21 expression but was circumvented by administration of an exogenous PPARγ agonist suggesting a linkage between cell cycling and PPARγ ligand production. Indeed, cell cycle inhibitory compounds decreased PPARγ ligand production in differentiating 3T3-L1 preadipocytes. Furthermore, these inhibitors abolished the release of arachidonic acid induced by the hormonal cocktail initiating adipogenesis. Collectively, our results suggest that murine fibroblasts require clonal expansion for PPARγ ligand production at the onset of adipocyte differentiation. PMID:25312885

Citrus aurantium L. dry extracts promote C/ebpβ expression and improve adipocyte differentiation in 3T3-L1 cells.

PubMed

Raciti, Gregory Alexander; Fiory, Francesca; Campitelli, Michele; Desiderio, Antonella; Spinelli, Rosa; Longo, Michele; Nigro, Cecilia; Pepe, Giacomo; Sommella, Eduardo; Campiglia, Pietro; Formisano, Pietro; Beguinot, Francesco; Miele, Claudia

2018-01-01

Metabolic and/or endocrine dysfunction of the white adipose tissue (WAT) contribute to the development of metabolic disorders, such as Type 2 Diabetes (T2D). Therefore, the identification of products able to improve adipose tissue function represents a valuable strategy for the prevention and/or treatment of T2D. In the current study, we investigated the potential effects of dry extracts obtained from Citrus aurantium L. fruit juice (CAde) on the regulation of 3T3-L1 cells adipocyte differentiation and function in vitro. We found that CAde enhances terminal adipocyte differentiation of 3T3-L1 cells raising the expression of CCAAT/enhancer binding protein beta (C/Ebpβ), peroxisome proliferator activated receptor gamma (Pparγ), glucose transporter type 4 (Glut4) and fatty acid binding protein 4 (Fabp4). CAde improves insulin-induced glucose uptake of 3T3-L1 adipocytes, as well. A focused analysis of the phases occurring in the pre-adipocytes differentiation to mature adipocytes furthermore revealed that CAde promotes the early differentiation stage by up-regulating C/ebpβ expression at 2, 4 and 8 h post the adipogenic induction and anticipating the 3T3-L1 cell cycle entry and progression during mitotic clonal expansion (MCE). These findings provide evidence that the exposure to CAde enhances in vitro fat cell differentiation of pre-adipocytes and functional capacity of mature adipocytes, and pave the way to the development of products derived from Citrus aurantium L. fruit juice, which may improve WAT functional capacity and may be effective for the prevention and/or treatment of T2D.

Characterization of lipid metabolism in insulin-sensitive adipocytes differentiated from immortalized human mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Prawitt, Janne; Niemeier, Andreas; Kassem, Moustapha

2008-02-15

There is a great demand for cell models to study human adipocyte function. Here we describe the adipogenic differentiation of a telomerase-immortalized human mesenchymal stem cell line (hMSC-Tert) that maintains numerous features of terminally differentiated adipocytes even after prolonged withdrawal of the peroxisome proliferator activated receptor {gamma} (PPAR{gamma}) agonist rosiglitazone. Differentiated hMSC-Tert developed the characteristic monolocular phenotype of mature adipocytes. The expression of adipocyte specific markers was highly increased during differentiation. Most importantly, the presence of the PPAR{gamma} agonist rosiglitazone was not required for the stable expression of lipoprotein lipase, adipocyte fatty acid binding protein and perilipin on mRNA andmore » protein levels. Adiponectin expression was post-transcriptionally down-regulated in the absence of rosiglitazone. Insulin sensitivity as measured by insulin-induced phosphorylation of Akt and S6 ribosomal protein was also independent of rosiglitazone. In addition to commonly used adipogenic markers, we investigated further PPAR{gamma}-stimulated proteins with a role in lipid metabolism. We observed an increase of lipoprotein receptor (VLDLR, LRP1) and apolipoprotein E expression during differentiation. Despite this increased expression, the receptor-mediated endocytosis of lipoproteins was decreased in differentiated adipocytes, suggesting that these proteins may have an additional function in adipose tissue beyond lipoprotein uptake.« less

Hydroxyframoside B, a secoiridoid of Fraxinus rhynchophylla, inhibits adipocyte differentiation in 3T3-L1 cells.

PubMed

Choi, Kyeong-Mi; Shin, Eunjin; Liu, Qing; Yoo, Hwan-Soo; Kim, Young Choong; Sung, Sang Hyun; Hwang, Bang Yeon; Lee, Mi Kyeong

2011-07-01

Fraxinus rhynchophylla showed significant inhibitory activity on adipocyte differentiation in the 3T3-L1 preadipocyte cell line as assessed by measuring fat accumulation using Oil Red O staining. Further fractionation led to the isolation of two secoiridoids, oleuropein and hydroxyframoside B. Hydroxyframoside B significantly reduced fat accumulation and triglyceride content in differentiated 3T3-L1 cells without affecting cell viability, whereas oleuropein showed little effect. Further studies with interval treatment demonstrated that hydroxyframoside B exerted inhibitory activity on adipocyte differentiation when treated within 2 days (days 0-2) after differentiation induction. In addition, hydroxyframoside B significantly blocked the induction of adipogenic transcription factors such as C/EBP α, C/EBP β, and PPAR γ. Taken together, these results suggest that hydroxyframoside B inhibited early/middle stage of adipogenic differentiation, in part, via inhibition of C/EBP α, C/EBP β, and PPAR γ-dependent pathways. © Georg Thieme Verlag KG Stuttgart · New York.

miR-199a-3p regulates brown adipocyte differentiation through mTOR signaling pathway.

PubMed

Gao, Yao; Cao, Yan; Cui, Xianwei; Wang, Xingyun; Zhou, Yahui; Huang, Fangyan; Wang, Xing; Wen, Juan; Xie, Kaipeng; Xu, Pengfei; Guo, Xirong; You, Lianghui; Ji, Chenbo

2018-05-10

Recent discoveries of functional brown adipocytes in mammals illuminates their therapeutic potential for combating obesity and its associated diseases. However, on account of the limited amount and activity in adult humans of brown adipocyte depots, identification of miRNAs and characterization their regulatory roles in human brown adipogenesis are urgently needed. This study focused on the role of microRNA (miR)-199a-3p in human brown adipocyte differentiation and thermogenic capacity. A decreased expression pattern of miR-199a-3p was consistently observed during the differentiation course of brown adipocytes in mice and humans. Conversely, its level was induced during the differentiation course of human white pre-adipocytes derived from visceral fat. miR-199a-3p expression was relatively abundant in interscapular BAT (iBAT) and differentially regulated in the activated and aging BAT in mice. Additionally, miR-199a-3p expression level in human brown adipocytes was observed decreased upon thermogenic activation and increased by aging-related stimuli. Using primary pre-adipocytes, miR-199a-3p over-expression was capable of attenuating lipid accumulation and adipogenic gene expression as well as impairing brown adipocytes' metabolic characteristics as revealed by decreased mitochondrial DNA content and respiration. Suppression of miR-199a-3p by a locked nucleic acid (LNA) modified-anti-miR led to increased differentiation and thermogenesis in human brown adipocytes. By combining target prediction and examination, we identified mechanistic target of rapamycin kinase (mTOR) as a direct target of miR-199a-3p that affected brown adipogenesis and thermogenesis. Our results point to a novel role for miR-199a-3p and its downstream effector mTOR in human brown adipocyte differentiation and maintenance of thermogenic characteristics, which can be manipulated as therapeutic targets against obesity and its related metabolic disorders. Copyright © 2018. Published by Elsevier B.V.

Nobiletin enhances differentiation and lipolysis of 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saito, Takeshi; Abe, Daigo; Sekiya, Keizo

2007-06-01

Nobiletin is a polymethoxylated flavone found in certain citrus fruits. Here we demonstrate that nobiletin enhance differentiation of 3T3-L1 preadipocytes. Nobiletin dose-dependently increased accumulation of lipid droplets in adipocytes. Quantitative RT-PCR analyses indicated that nobiletin increased the expression of genes critical for acquisition of the adipocyte phenotype. Some of them were known peroxisome proliferator activated receptor {gamma} (PPAR{gamma}) targets and PPAR{gamma} itself, however, nobiletin did not exhibit PPAR{gamma} ligand activity. We observed the expression of CCAAT/enhancer binding protein {beta} (C/EBP{beta}), a transcription factor for PPAR{gamma}, was increased by nobiletin. The activation of cAMP-responsive element binding protein (CREB) and extracellular signal-regulatedmore » kinase (ERK), which play important roles in C/EBP{beta} expression were also potentiated by nobiletin. Furthermore, nobiletin stimulated lipolysis in differentiated adipocytes, which is known to be stimulated by cAMP pathway. These results suggested that nobiletin enhanced both differentiation and lipolysis of adipocyte through activation of signaling cascades mediated by cAMP/CREB.« less

The brown adipocyte differentiation pathway in birds: An evolutionary road not taken

PubMed Central

Mezentseva, Nadejda V; Kumaratilake, Jaliya S; Newman, Stuart A

2008-01-01

Background Thermogenic brown adipose tissue has never been described in birds or other non-mammalian vertebrates. Brown adipocytes in mammals are distinguished from the more common white fat adipocytes by having numerous small lipid droplets rather than a single large one, elevated numbers of mitochondria, and mitochondrial expression of the nuclear gene UCP1, the uncoupler of oxidative phosphorylation responsible for non-shivering thermogenesis. Results We have identified in vitro inductive conditions in which mesenchymal cells isolated from the embryonic chicken limb bud differentiate into avian brown adipocyte-like cells (ABALCs) with the morphological and many of the biochemical properties of terminally differentiated brown adipocytes. Avian, and as we show here, lizard species lack the gene for UCP1, although it is present in amphibian and fish species. While ABALCs are therefore not functional brown adipocytes, they are generated by a developmental pathway virtually identical to brown fat differentiation in mammals: both the common adipogenic transcription factor peroxisome proliferator-activated receptor-γ (PPARγ), and a coactivator of that factor specific to brown fat differentiation in mammals, PGC1α, are elevated in expression, as are mitochondrial volume and DNA. Furthermore, ABALCs induction resulted in strong transcription from a transfected mouse UCP1 promoter. Conclusion These findings strongly suggest that the brown fat differentiation pathway evolved in a common ancestor of birds and mammals and its thermogenicity was lost in the avian lineage, with the degradation of UCP1, after it separated from the mammalian lineage. Since this event occurred no later than the saurian ancestor of birds and lizards, an implication of this is that dinosaurs had neither UCP1 nor canonically thermogenic brown fat. PMID:18426587

MicroRNA-200a regulates adipocyte differentiation in the domestic yak Bos grunniens.

PubMed

Zhang, Yongfeng; Wu, Xiaoyun; Liang, Chunnian; Bao, Pengjia; Ding, Xuezhi; Chu, Min; Jia, Congjun; Guo, Xian; Yan, Ping

2018-04-15

The domestic yak (Bos grunniens) is a culturally important animal that lives at high altitude and is farmed by Tibetan herders for its meat, milk, and other animal by-products. Within the animal, adipose tissue is an important store and source of energy and is used to maintain adequate body temperature during the extended cold seasons. Exploring the biomolecular role of microRNAs (miRNAs) in the regulation of growth, development, and metabolism of yak adipocytes may provide valuable insights into the physiology of adipogenesis in the yak. This study investigated whether and how miR-200a (a miRNA recently reported to promote adipogenesis in ST2 bone marrow stromal cells) regulates adipocyte differentiation in the yak. Expression levels of miR-200a gradually increased during day 0 to day 8 of adipocyte differentiation, and transfection of adipocytes with miR-200a enhanced lipid accumulation and triglyceride content compared to control (un-transfected) adipocytes. We additionally verified (using qRT-PCR analysis) that miR-200a increased the expression of adipocyte-specific genes involved in lipogenic transcription (PPARγ, ELVOL, and C/EBPα), fatty acid synthesis (ACC, ACS, SCD, and FAS), and fatty acid transport (DGAT, LPL, and FABP4). We also found that transfection of adipocytes with miR-200a resulted in suppression of the levels of noncanonical Wnt signaling transcription factors (Wnt5a, TAK1, and NLK). These results indicate that miRNA-200a plays an important role in promoting yak adipocyte differentiation that may operate via the suppression of noncanonical Wnt signaling. Copyright © 2018 Elsevier B.V. All rights reserved.

Impaired preadipocyte differentiation into adipocytes in subcutaneous abdominal adipose of PCOS-like female rhesus monkeys.

PubMed

Keller, Erica; Chazenbalk, Gregorio D; Aguilera, Paul; Madrigal, Vanessa; Grogan, Tristan; Elashoff, David; Dumesic, Daniel A; Abbott, David H

2014-07-01

Metabolic characteristics of polycystic ovary syndrome women and polycystic ovary syndrome-like, prenatally androgenized (PA) female monkeys worsen with age, with altered adipogenesis of sc abdominal adipose potentially contributing to age-related adverse effects on metabolism. This study examines whether adipocyte morphology and gene expression in sc abdominal adipose differ between late reproductive-aged PA female rhesus monkeys compared with age-matched controls (C). Subcutaneous abdominal adipose of both groups was obtained for histological imaging and mRNA determination of zinc finger protein 423 (Zfp423) as a marker of adipose stem cell commitment to preadipocytes, and CCAAT/enhancer binding protein (C/EBP)α/peroxisome proliferator-activated receptor (PPAR)δ as well as C/EBPα/PPARγ as respective markers of early- and late-stage differentiation of preadipocytes to adipocytes. In all females combined, serum testosterone (T) levels positively correlated with fasting serum levels of total free fatty acid (r(2) = 0.73, P < .002). PA females had a greater population of small adipocytes vs C (P < .001) in the presence of increased Zfp423 (P < .025 vs C females) and decreased C/EBPα (P < .003, vs C females) mRNA expression. Moreover, Zfp423 mRNA expression positively correlated with circulating total free fatty acid levels during iv glucose tolerance testing (P < .004, r(2) = 0.66), whereas C/EBPα mRNA expression negatively correlated with serum T levels (P < .02, r(2) = 0.43). Gene expression of PPARδ and PPARγ were comparable between groups (P = .723 and P = .18, respectively). Early-to-mid gestational T excess in female rhesus monkeys impairs adult preadipocyte differentiation to adipocytes in sc abdominal adipose and may constrain the ability of this adipose depot to safely store fat with age.

Mechanism of Regulation of Adipocyte Numbers in Adult Organisms Through Differentiation and Apoptosis Homeostasis

PubMed Central

Bozec, Aline; Hannemann, Nicole

2016-01-01

Considering that adipose tissue (AT) is an endocrine organ, it can influence whole body metabolism. Excessive energy storage leads to the dysregulation of adipocytes, which in turn induces abnormal secretion of adipokines, triggering metabolic syndromes such as obesity, dyslipidemia, hyperglycemia, hyperinsulinemia, insulin resistance and type 2 diabetes. Therefore, investigating the molecular mechanisms behind adipocyte dysregulation could help to develop novel therapeutic strategies. Our protocol describes methods for evaluating the molecular mechanism affected by hypoxic conditions of the AT, which correlates with adipocyte apoptosis in adult mice. This protocol describes how to analyze AT in vivo through gene expression profiling as well as histological analysis of adipocyte differentiation, proliferation and apoptosis during hypoxia exposure, ascertained through staining of hypoxic cells or HIF-1α protein. Furthermore, in vitro analysis of adipocyte differentiation and its responses to various stimuli completes the characterization of the molecular pathways behind possible adipocyte dysfunction leading to metabolic syndromes. PMID:27284940

Mechanism of Regulation of Adipocyte Numbers in Adult Organisms Through Differentiation and Apoptosis Homeostasis.

PubMed

Bozec, Aline; Hannemann, Nicole

2016-06-03

Considering that adipose tissue (AT) is an endocrine organ, it can influence whole body metabolism. Excessive energy storage leads to the dysregulation of adipocytes, which in turn induces abnormal secretion of adipokines, triggering metabolic syndromes such as obesity, dyslipidemia, hyperglycemia, hyperinsulinemia, insulin resistance and type 2 diabetes. Therefore, investigating the molecular mechanisms behind adipocyte dysregulation could help to develop novel therapeutic strategies. Our protocol describes methods for evaluating the molecular mechanism affected by hypoxic conditions of the AT, which correlates with adipocyte apoptosis in adult mice. This protocol describes how to analyze AT in vivo through gene expression profiling as well as histological analysis of adipocyte differentiation, proliferation and apoptosis during hypoxia exposure, ascertained through staining of hypoxic cells or HIF-1α protein. Furthermore, in vitro analysis of adipocyte differentiation and its responses to various stimuli completes the characterization of the molecular pathways behind possible adipocyte dysfunction leading to metabolic syndromes.

Retinoic acid receptor signalling directly regulates osteoblast and adipocyte differentiation from mesenchymal progenitor cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Green, A.C.; Department of Medicine at St. Vincent's Hospital, The University of Melbourne, Victoria 3065; Kocovski, P.

Low and high serum retinol levels are associated with increased fracture risk and poor bone health. We recently showed retinoic acid receptors (RARs) are negative regulators of osteoclastogenesis. Here we show RARs are also negative regulators of osteoblast and adipocyte differentiation. The pan-RAR agonist, all-trans retinoic acid (ATRA), directly inhibited differentiation and mineralisation of early osteoprogenitors and impaired the differentiation of more mature osteoblast populations. In contrast, the pan-RAR antagonist, IRX4310, accelerated differentiation of early osteoprogenitors. These effects predominantly occurred via RARγ and were further enhanced by an RARα agonist or antagonist, respectively. RAR agonists similarly impaired adipogenesis in osteogenicmore » cultures. RAR agonist treatment resulted in significant upregulation of the Wnt antagonist, Sfrp4. This accompanied reduced nuclear and cytosolic β-catenin protein and reduced expression of the Wnt target gene Axin2, suggesting impaired Wnt/β-catenin signalling. To determine the effect of RAR inhibition in post-natal mice, IRX4310 was administered to male mice for 10 days and bones were assessed by µCT. No change to trabecular bone volume was observed, however, radial bone growth was impaired. These studies show RARs directly influence osteoblast and adipocyte formation from mesenchymal cells, and inhibition of RAR signalling in vivo impairs radial bone growth in post-natal mice. - Graphical abstract: Schematic shows RAR ligand regulation of osteoblast differentiation in vitro. RARγ antagonists±RARα antagonists promote osteoblast differentiation. RARγ and RARα agonists alone or in combination block osteoblast differentiation, which correlates with upregulation of Sfrp4, and downregulation of nuclear and cytosolic β-catenin and reduced expression of the Wnt target gene Axin2. Red arrows indicate effects of RAR agonists on mediators of Wnt signalling.« less

Coprinus comatus Cap Inhibits Adipocyte Differentiation via Regulation of PPARγ and Akt Signaling Pathway

PubMed Central

Jang, Sun-Hee; Kang, Suk Nam; Jeon, Beong-Sam; Ko, Yeoung-Gyu; Kim, Hong-Duck; Won, Chung-Kil; Kim, Gon-Sup; Cho, Jae-Hyeon

2014-01-01

This study assessed the effects of Coprinus comatus cap (CCC) on adipogenesis in 3T3-L1 adipocytes and the effects of CCC on the development of diet-induced obesity in rats. Here, we showed that the CCC has an inhibitory effect on the adipocyte differentiation of 3T3-L1 cells, resulting in a significant decrease in lipid accumulation through the downregulation of several adipocyte specific-transcription factors, including CCAAT/enhancer binding protein β, C/EBPδ, and peroxisome proliferator-activated receptor gamma (PPARγ). Moreover, treatment with CCC during adipocyte differentiation induced a significant down-regulation of PPARγ and adipogenic target genes, including adipocyte protein 2, lipoprotein lipase, and adiponectin. Interestingly, the CCC treatment of the 3T3-L1 adipocytes suppressed the insulin-stimulated Akt and GSK3β phosphorylation, and these effects were stronger in the presence of an inhibitor of Akt phosphorylation, LY294002, suggesting that CCC inhibited adipocyte differentiation through the down-regulation of Akt signaling. In the animal study, CCC administration significantly reduced the body weight and adipose tissue weight of rats fed a high fat diet (HFD) and attenuated lipid accumulation in the adipose tissues of the HFD-induced obese rats. The size of the adipocyte in the epididymal fat of the CCC fed rats was significantly smaller than in the HFD rats. CCC treatment significantly reduced the total cholesterol and triglyceride levels in the serum of HFD rats. These results strongly indicated that the CCC-mediated decrease in body weight was due to a reduction in adipose tissue mass. The expression level of PPARγ and phospho-Akt was significantly lower in the CCC-treated HFD rats than that in the HFD obesity rats. These results suggested that CCC inhibited adipocyte differentiation by the down-regulation of major transcription factor involved in the adipogenesis pathway including PPARγ through the regulation of the Akt pathway in 3T3

γ-Oryzanol Enhances Adipocyte Differentiation and Glucose Uptake

PubMed Central

Jung, Chang Hwa; Lee, Da-Hye; Ahn, Jiyun; Lee, Hyunjung; Choi, Won Hee; Jang, Young Jin; Ha, Tae-Youl

2015-01-01

Recent studies show that brown rice improves glucose intolerance and potentially the risk of diabetes, although the underlying molecular mechanisms remain unclear. One of the phytochemicals found in high concentration in brown rice is γ-oryzanol (Orz), a group of ferulic acid esters of phytosterols and triterpene alcohols. Here, we found that Orz stimulated differentiation of 3T3-L1 preadipocytes and increased the protein expression of adipogenic marker genes such as peroxisome proliferator-activated receptor gamma (PPAR-γ) and CCAAT/enhanced binding protein alpha (C/EBPα). Moreover, Orz significantly increased the glucose uptake in insulin-resistant cells and translocation of glucose transporter type 4 (GLUT4) from the cytosol to the cell surface. To investigate the mechanism by which Orz stimulated cell differentiation, we examined its effects on cellular signaling of the mammalian target of rapamycin complex 1 (mTORC1), a central mediator of cellular growth and proliferation. The Orz treatment increased mTORC1 kinase activity based on phosphorylation of 70-kDa ribosomal S6 kinase 1 (S6K1). The effect of Orz on adipocyte differentiation was dependent on mTORC1 activity because rapamycin blocks cell differentiation in Orz-treated cells. Collectively, our results indicate that Orz stimulates adipocyte differentiation, enhances glucose uptake, and may be associated with cellular signaling mediated by PPAR-γ and mTORC1. PMID:26083118

γ-Oryzanol Enhances Adipocyte Differentiation and Glucose Uptake.

PubMed

Jung, Chang Hwa; Lee, Da-Hye; Ahn, Jiyun; Lee, Hyunjung; Choi, Won Hee; Jang, Young Jin; Ha, Tae-Youl

2015-06-15

Recent studies show that brown rice improves glucose intolerance and potentially the risk of diabetes, although the underlying molecular mechanisms remain unclear. One of the phytochemicals found in high concentration in brown rice is γ-oryzanol (Orz), a group of ferulic acid esters of phytosterols and triterpene alcohols. Here, we found that Orz stimulated differentiation of 3T3-L1 preadipocytes and increased the protein expression of adipogenic marker genes such as peroxisome proliferator-activated receptor gamma (PPAR-γ) and CCAAT/enhanced binding protein alpha (C/EBPα). Moreover, Orz significantly increased the glucose uptake in insulin-resistant cells and translocation of glucose transporter type 4 (GLUT4) from the cytosol to the cell surface. To investigate the mechanism by which Orz stimulated cell differentiation, we examined its effects on cellular signaling of the mammalian target of rapamycin complex 1 (mTORC1), a central mediator of cellular growth and proliferation. The Orz treatment increased mTORC1 kinase activity based on phosphorylation of 70-kDa ribosomal S6 kinase 1 (S6K1). The effect of Orz on adipocyte differentiation was dependent on mTORC1 activity because rapamycin blocks cell differentiation in Orz-treated cells. Collectively, our results indicate that Orz stimulates adipocyte differentiation, enhances glucose uptake, and may be associated with cellular signaling mediated by PPAR-γ and mTORC1.

5-Hydroxyferulic acid methyl ester isolated from wasabi leaves inhibits 3T3-L1 adipocyte differentiation.

PubMed

Misawa, Naoki; Hosoya, Takahiro; Yoshida, Shuhei; Sugimoto, Osamu; Yamada-Kato, Tomoe; Kumazawa, Shigenori

2018-02-26

To investigate the compounds present in wasabi leaves (Wasabia japonica Matsumura) that inhibit the adipocyte differentiation, activity-guided fractionation was performed on these leaves. 5-Hydroxyferulic acid methyl ester (1: 5-HFA ester), one of the phenylpropanoids, was isolated from wasabi leaves as a compound that inhibits the adipocyte differentiation. Compound 1 suppressed the intracellular lipid accumulation of 3T3-L1 cells without significant cytotoxicity. Gene expression analysis revealed that 1 suppressed the mRNA expression of 2 master regulators of adipocyte differentiation, PPARγ and C/EBPα. Furthermore, 1 downregulated the expression of adipogenesis-related genes, GLUT4, LPL, SREBP-1c, ACC, and FAS. Protein expression analysis revealed that 1 suppressed PPARγ protein expression. Moreover, to investigate the relationship between the structure and activity of inhibiting the adipocyte differentiation, we synthesized 12 kinds of phenylpropanoid analog. Comparison of the activity among 1 and its analogs suggested that the compound containing the substructure that possess a common functional group at the ortho position such as a catechol group exhibits the activity of inhibiting the adipocyte differentiation. Taken together, our findings suggest that 1 from wasabi leaves inhibits adipocyte differentiation via the downregulation of PPARγ. Copyright © 2018 John Wiley & Sons, Ltd.

Inhibitory effect of leptin on rosiglitazone-induced differentiation of primary adipocytes prepared from TallyHO/Jng mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Ki Young; Kim, Joo Young; Sung, Yoon-Young

2011-03-25

Research highlights: {yields} In this study, we investigated the effects of leptin on adipocyte differentiation prepared from subcutaneous fat of TallyHo mice. {yields} Leptin inhibited the adipocytes differentiation at physiological concentration via inhibition of PPAR{gamma} expression. {yields} Inhibitors of ERK and STAT1 restored the leptin's inhibitory activity both in vitro and in vivo. -- Abstract: The effects of leptin on rosiglitazone-induced adipocyte differentiation were investigated in the primary adipocytes prepared from subcutaneous fat of TallyHO/Jng (TallyHO) mouse, a recently developed model animal for type 2 diabetes mellitus (T2DM). The treatment of leptin inhibited the rosiglitazone-induced adipocyte differentiation with a decreasedmore » expression of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) a key adipogenic transcription factor, both in mRNA and protein levels. Leptin (10 nM) was sufficient to inhibit the adipocyte differentiation, which seemed to come from increased expression of leptin receptor genes in the fat of TallyHO mice. The inhibition of adipogenesis by leptin was restored by the treatment of inhibitors for extracellular-signal-regulated kinase (ERK) (PD98059) and signal transducer and activator of transcription-1 (STAT1) (fludarabine). Furthermore, in vivo intraperitoneal administration of PD98059 and fludarabine increased the PPAR{gamma} expression in the subcutaneous fat of TallyHO mice. These data suggest that leptin could inhibit the PPAR{gamma} expression and adipocyte differentiation in its physiological concentration in TallyHO mice.« less

The effects of perfluorinated chemicals on adipocyte differentiation in vitro.

PubMed

Watkins, Andrew M; Wood, Carmen R; Lin, Mimi T; Abbott, Barbara D

2015-01-15

The 3T3-L1 preadipocyte culture system has been used to examine numerous compounds that influence adipocyte differentiation or function. The perfluoroalkyl acids (PFAAs), used as surfactants in a variety of industrial applications, are of concern as environmental contaminants that are detected worldwide in human serum and animal tissues. This study was designed to evaluate the potential for PFAAs to affect adipocyte differentiation and lipid accumulation using mouse 3T3-L1 cells. Cells were treated with perfluorooctanoic acid (PFOA) (5-100 µM), perfluorononanoic acid (PFNA) (5-100 µM), perfluorooctane sulfonate (PFOS) (50-300 µM), perfluorohexane sulfonate (PFHxS) (40-250 µM), the peroxisome proliferator activated receptor (PPAR) PPARα agonist Wyeth-14,643 (WY-14,643), and the PPARγ agonist rosiglitazone. The PPARγ agonist was included as a positive control as this pathway is critical to adipocyte differentiation. The PPARα agonist was included as the PFAA compounds are known activators of this pathway. Cells were assessed morphometrically and biochemically for number, size, and lipid content. RNA was extracted for qPCR analysis of 13 genes selected for their importance in adipocyte differentiation and lipid metabolism. There was a significant concentration-related increase in cell number and decreased cell size after exposure to PFOA, PFHxS, PFOS, and PFNA. All four PFAA treatments produced a concentration-related decrease in the calculated average area occupied by lipid per cell. However, total triglyceride levels per well increased with a concentration-related trend for all compounds, likely due to the increased cell number. Expression of mRNA for the selected genes was affected by all exposures and the specific impacts depended on the particular compound and concentration. Acox1 and Gapdh were upregulated by all six compounds. The strongest overall effect was a nearly 10-fold induction of Scd1 by PFHxS. The sulfonated PFAAs produced numerous

Experimental Model to Study the Role of Retinoblastoma Gene Product (pRb) for Determination of Adipocyte Differentiation.

PubMed

Popov, B V; Shilo, P S; Zhidkova, O V; Zaichik, A M; Petrov, N S

2015-06-01

Using stable constitutive expression of retinoblastoma gene product (pRb) in polypotent mesenchymal 10T1/2 cells we obtained stable cell lines hyperexpressing functionally active or inactive mutant pRb. The cells producing active exogenous pRb demonstrated high sensitivity to adipocyte differentiation inductors, whereas production of inactive form of the exogenous protein suppressed adipocyte differentiation. The obtained lines can serve as the experimental model for studying the role of pRb in determination of adipocyte differentiation.

A novel brown adipocyte-enriched long non-coding RNA that is required for brown adipocyte differentiation and sufficient to drive thermogenic gene program in white adipocytes.

PubMed

Xiong, Yan; Yue, Feng; Jia, Zhihao; Gao, Yun; Jin, Wen; Hu, Keping; Zhang, Yong; Zhu, Dahai; Yang, Gongshe; Kuang, Shihuan

2018-04-01

The thermogenic activities of brown and beige adipocytes can be exploited to reduce energy surplus and counteract obesity. Recent RNA sequencing studies have uncovered a number of long noncoding RNAs (lncRNAs) uniquely expressed in white and brown adipose tissues (WAT and BAT), but whether and how these lncRNAs function in adipogenesis remain largely unknown. Here, we report the identification of a novel brown adipocyte-enriched LncRNA (AK079912), and its nuclear localization, function and regulation. The expression of AK079912 increases during brown preadipocyte differentiation and in response to cold-stimulated browning of white adipocytes. Knockdown of AK079912 inhibits brown preadipocyte differentiation, manifested by reductions in lipid accumulation and down-regulation of adipogenic and BAT-specific genes. Conversely, ectopic expression of AK079912 in white preadipocytes up-regulates the expression of genes involved in thermogenesis. Mechanistically, inhibition of AK079912 reduces mitochondrial copy number and protein levels of mitochondria electron transport chain (ETC) complexes, whereas AK079912 overexpression increases the levels of ETC proteins. Lastly, reporter and pharmacological assays identify Pparγ as an upstream regulator of AK079912. These results provide new insights into the function of non-coding RNAs in brown adipogenesis and regulating browning of white adipocytes. Copyright © 2018 Elsevier B.V. All rights reserved.

Early endocrine disruptors exposure acts on 3T3-L1 differentiation and endocrine activity

PubMed Central

Boudalia, Sofiane; Belloir, Christine; Miller, Marie-Louise; Canivenc-Lavier, Marie-Chantal

2017-01-01

Introduction: Data from last years suggested that early exposure to endocrine disruptors (EDs) can predispose newborns to endocrine dysfunction of adipocytes, obesity, and associated disorders. The implication of EDs at low doses on adipocyte development has been poorly investigated. For instance, vinclozolin (V) is a dicarboximide fungicide widely used in agriculture since the 90's, alone or in mixture with genistein (G), an isoflavonoid from Leguminosae. This study aims to identify the effect of vinclozolin alone or with genistein, on adipose tissue properties using cell culture. Methods: In steroid-free conditions, 3T3-L1 pre-adipocytes were induced to differentiate in the presence of EDs, singularly or in mixtures, for 2 days. DNA and triglyceride (TG) levels were measured on days 0, 2 and 8 of differentiation. Leptin secretion was measured only on the eighth day. Results: We show that low doses of G (25 µM) and V (0.1 µM) inhibit pre-adipocytes differentiation. This inhibition has been represented by a decreasing in DNA content (µg/well) and decreasing in TG accumulation (mg/mL) in 3T3-L1 cells. Nevertheless, V increased the anti-adipogenic properties of G. Conclusion: This study confirms that EDs singularly or in mixtures, introduced during early stages of life, could affect the differentiation and the endocrine activity of adipocytes, and can act as potential factors for obesity. PMID:28752072

CUDC-907 Promotes Bone Marrow Adipocytic Differentiation Through Inhibition of Histone Deacetylase and Regulation of Cell Cycle.

PubMed

Ali, Dalia; Alshammari, Hassan; Vishnubalaji, Radhakrishnan; Chalisserry, Elna Paul; Hamam, Rimi; Alfayez, Musaad; Kassem, Moustapha; Aldahmash, Abdullah; Alajez, Nehad M

2017-03-01

The role of bone marrow adipocytes (BMAs) in overall energy metabolism and their effects on bone mass are currently areas of intensive investigation. BMAs differentiate from bone marrow stromal cells (BMSCs); however, the molecular mechanisms regulating BMA differentiation are not fully understood. In this study, we investigated the effect of CUDC-907, identified by screening an epigenetic small-molecule library, on adipocytic differentiation of human BMSCs (hBMSCs) and determined its molecular mechanism of action. Human bone marrow stromal cells exposed to CUDC-907 (500 nM) exhibited enhanced adipocytic differentiation (∼2.9-fold increase, P < 0.005) compared with that of control cells. Global gene expression and signaling pathway analyses of differentially expressed genes revealed a strong enrichment of genes involved in adipogenesis, cell cycle, and DNA replication. Chromatin immune precipitation combined with quantitative polymerase chain reaction showed significant increase in H3K9ac epigenetic marker in the promoter regions of AdipoQ, FABP4, PPARγ, KLF15, and CEBPA in CUDC-907-treated hBMSCs. Follow-up experiments corroborated that the inhibition of histone deacetylase (HDAC) activity enhanced adipocytic differentiation, while the inhibition of PI3K decreased adipocytic differentiation. In addition, CUDC-907 arrested hBMSCs in the G0-G1 phase of the cell cycle and reduced the number of S-phase cells. Our data reveal that HDAC, PI3K, and cell cycle genes are important regulators of BMA formation and demonstrate that adipocyte differentiation of hBMSCs is associated with complex changes in a number of epigenetic and genetic pathways, which can be targeted to regulate BMA formation.

Anti-Inflammatory Effect of Spirulina platensis in Macrophages Is Beneficial for Adipocyte Differentiation and Maturation by Inhibiting Nuclear Factor-κB Pathway in 3T3-L1 Adipocytes.

PubMed

Pham, Tho X; Lee, Ji-Young

2016-06-01

We previously showed that the organic extract of a blue-green alga, Spirulina platensis (SPE), had potent anti-inflammatory effects in macrophages. As the interplay between macrophages and adipocytes is critical for adipocyte functions, we investigated the contribution of the anti-inflammatory effects of SPE in macrophages to adipogenesis/lipogenesis in 3T3-L1 adipocytes. 3T3-L1 preadipocytes were treated with 10% conditioned medium from lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages (CMC) or LPS-stimulated, but SPE-pretreated, macrophages (CMS) at different stages of adipocyte differentiation. The expression of adipocyte differentiation markers, such as CCAAT/enhancer-binding protein α, peroxisome proliferator-activated receptor γ, and perilipin, was significantly repressed by CMC when added on day 3, while the repression was attenuated by CMS. Oil Red O staining confirmed that adipocyte maturation in CMS-treated cells, but not in CMC-treated cells, was equivalent to that of control cells. Nuclear translocation of nuclear factor κB (NF-κB) p65 was decreased by CMS compared to CMC. In lipid-laden adipocytes, CMC promoted the loss of lipid droplets, while CMS had minimal effects. Histone deacetylase 9 mRNA and protein levels were increased during adipocyte maturation, which were decreased by CMC. In conclusion, by cross-talking with adipocytes, the anti-inflammatory effects of SPE in macrophages promoted adipocyte differentiation/maturation, at least in part, by repressing the activation of NF-κB inflammatory pathways, which otherwise can be compromised in inflammatory conditions.

Osteopontin-deficient progenitor cells display enhanced differentiation to adipocytes.

PubMed

Moreno-Viedma, Veronica; Tardelli, Matteo; Zeyda, Maximilian; Sibilia, Maria; Burks, J Deborah; Stulnig, Thomas M

2018-03-06

Osteopontin (OPN, Spp1) is a protein upregulated in white adipose tissue (WAT) of obese subjects. Deletion of OPN protects mice from high-fat diet-induced WAT inflammation and insulin resistance. However, the alterations mediated by loss of OPN in WAT before the obesogenic challenge have not yet been investigated. Therefore, we hypothesised that the lack of OPN might enhance the pro-adipogenic micro environment before obesity driven inflammation. OPN deficiency was tested in visceral (V) and subcutaneous (SC) WAT from WT and Spp1 -/- female mice. Gene expression for hypoxia, inflammation and adipogenesis was checked in WT vs. Spp1 -/- mice (n=15). Adipocytes progenitor cells (APC) were isolated by fluorescence cell sorting and role of OPN deficiency in adipogenesis was investigated by cell images and RT-PCR. We show that Spp1 -/- maintained normal body and fat-pad weights, although hypoxia and inflammation markers were significantly reduced. In contrast, expression of genes involved in adipogenesis was increased in WAT from Spp1 -/- mice. Strikingly, APC from Spp1 -/- were diminished but differentiated more efficiently to adipocytes than those from control mice. APC from SC-WAT of lean OPN-deficient mice display an enhanced capacity for differentiating to adipocytes. These alterations may explain the healthy expansion of WAT in the OPN-deficient model which is associated with reduced inflammation and insulin resistance. Copyright © 2018. Published by Elsevier Ltd.

Romidepsin Promotes Osteogenic and Adipocytic Differentiation of Human Mesenchymal Stem Cells through Inhibition of Histondeacetylase Activity

PubMed Central

Ali, Dalia; Manikandan, Muthurangan; Hamam, Rimi; Alfayez, Musaad; Aldahmash, Abdullah

2018-01-01

Bone marrow mesenchymal stem cells (BMSCs) are adult multipotent stem cells that can differentiate into mesodermal lineage cells, including adipocytes and osteoblasts. However, the epigenetic mechanisms governing the lineage-specific commitment of BMSCs into adipocytes or osteoblasts are under investigation. Herein, we investigated the epigenetic effect of romidepsin, a small molecule dual inhibitor targeting HDAC1 and HDAC2 identified through an epigenetic library functional screen. BMSCs exposed to romidepsin (5 nM) exhibited enhanced adipocytic and osteoblastic differentiation. Global gene expression and signaling pathway analyses of differentially expressed genes revealed a strong enrichment of genes involved in adipogenesis and osteogenesis in romidepsin-treated BMSCs during induction into adipocytes or osteoblasts, respectively. Pharmacological inhibition of FAK signaling during adipogenesis or inhibition of FAK or TGFβ signaling during osteogenesis diminished the biological effects of romidepsin on BMSCs. The results of chromatin immunoprecipitation combined with quantitative polymerase chain reaction indicated a significant increase in H3K9Ac epigenetic markers in the promoter regions of peroxisome proliferator-activated receptor gamma (PPARγ) and KLF15 (related to adipogenesis) or SP7 (Osterix) and alkaline phosphatase (ALP) (related to osteogenesis) in romidepsin-treated BMSCs. Our data indicated that romidepsin is a novel in vitro modulator of adipocytic and osteoblastic differentiation of BMSCs. PMID:29731773

Romidepsin Promotes Osteogenic and Adipocytic Differentiation of Human Mesenchymal Stem Cells through Inhibition of Histondeacetylase Activity.

PubMed

Ali, Dalia; Chalisserry, Elna P; Manikandan, Muthurangan; Hamam, Rimi; Alfayez, Musaad; Kassem, Moustapha; Aldahmash, Abdullah; Alajez, Nehad M

2018-01-01

Bone marrow mesenchymal stem cells (BMSCs) are adult multipotent stem cells that can differentiate into mesodermal lineage cells, including adipocytes and osteoblasts. However, the epigenetic mechanisms governing the lineage-specific commitment of BMSCs into adipocytes or osteoblasts are under investigation. Herein, we investigated the epigenetic effect of romidepsin, a small molecule dual inhibitor targeting HDAC1 and HDAC2 identified through an epigenetic library functional screen. BMSCs exposed to romidepsin (5 nM) exhibited enhanced adipocytic and osteoblastic differentiation. Global gene expression and signaling pathway analyses of differentially expressed genes revealed a strong enrichment of genes involved in adipogenesis and osteogenesis in romidepsin-treated BMSCs during induction into adipocytes or osteoblasts, respectively. Pharmacological inhibition of FAK signaling during adipogenesis or inhibition of FAK or TGF β signaling during osteogenesis diminished the biological effects of romidepsin on BMSCs. The results of chromatin immunoprecipitation combined with quantitative polymerase chain reaction indicated a significant increase in H3K9Ac epigenetic markers in the promoter regions of peroxisome proliferator-activated receptor gamma (PPAR γ ) and KLF15 (related to adipogenesis) or SP7 (Osterix) and alkaline phosphatase (ALP) (related to osteogenesis) in romidepsin-treated BMSCs. Our data indicated that romidepsin is a novel in vitro modulator of adipocytic and osteoblastic differentiation of BMSCs.

Peroxisome Proliferator-Activated Receptor (PPAR) in Regenerative Medicine: Molecular Mechanism for PPAR in Stem Cells' Adipocyte Differentiation.

PubMed

Xie, Qiang; Tian, Taoran; Chen, Zhaozhao; Deng, Shuwen; Sun, Ke; Xie, Jing; Cai, Xiaoxiao

2016-01-01

Regenerative medicine plays an indispensable role in modern medicine and many trials and researches have therefore been developed to fit our medical needs. Tissue engineering has proven that adipose tissue can widely be used and brings advantages to regenerative medicine. Moreover, a trait of adipose stem cells being isolated and grown in vitro is a cornerstone to various applications. Since the adipose tissue has been widely used in regenerative medicine, numerous studies have been conducted to seek methods for gaining more adipocytes. To investigate molecular mechanism for adipocyte differentiation, peroxisome proliferator-activated receptor (PPAR) has been widely studied to find out its functional mechanism, as a key factor for adipocyte differentiation. However, the precise molecular mechanism is still unknown. This review thus summarizes recent progress on the study of molecular mechanism and role of PPAR in adipocyte differentiation.

Comparative analysis of human UCB and adipose tissue derived mesenchymal stem cells for their differentiation potential into brown and white adipocytes.

PubMed

Rashnonejad, Afrooz; Ercan, Gulinnaz; Gunduz, Cumhur; Akdemir, Ali; Tiftikcioglu, Yigit Ozer

2018-06-01

The differentiation potential of umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) into brown and white adipocytes in comparison to Adipose tissue derived MSCs (AD-MSCs) were investigated in order to characterize their potency for future cell therapies. MSCs were isolated from ten UCB samples and six liposuction materials. MSCs were differentiated into white and brown adipocytes after characterization by flow cytometry. Differentiated adipocytes were stained with Oil Red O and hematoxylin/eosin. The UCP1 protein levels in brown adipocytes were investigated by immunofluoresence and western blot analysis. Cells that expressed mesenchymal stem cells markers (CD34-, CD45-, CD90+ and CD105+) were successfully isolated from UCB and adipose tissue. Oil Red O staining demonstrated that white and brown adipocytes obtained from AD-MSCs showed 85 and 61% of red pixels, while it was 3 and 1.9%, respectively for white and brown adipocytes obtained from UCB-MSCs. Fluorescence microscopy analysis showed strong uncoupling protein 1 (UCP1) signaling in brown adipocytes, especially which were obtained from AD-MSCs. Quantification of UCP1 protein amount showed 4- and 10.64-fold increase in UCP1 contents of brown adipocytes derived from UCB-MSCs and AD-MSCs, respectively in comparison to undifferentiated MSCs (P < 0.004). UCB-MSCs showed only a little differentiation tendency into adipocytes means it is not an appropriate stem cell type to be differentiated into these cell types. In contrast, high differentiation efficiency of AD-MSCs into brown and white adipocytes make it appropriate stem cell type to use in future regenerative medicine of soft tissue disorders or fighting with obesity and its related disorders.

Nuclear organization during in vitro differentiation of porcine mesenchymal stem cells (MSCs) into adipocytes.

PubMed

Stachecka, Joanna; Walczak, Agnieszka; Kociucka, Beata; Ruszczycki, Błażej; Wilczyński, Grzegorz; Szczerbal, Izabela

2018-02-01

Differentiation of progenitor cells into adipocytes is accompanied by remarkable changes in cell morphology, cytoskeletal organization, and gene expression profile. Mature adipocytes are filled with a large lipid droplet and the nucleus tends to move to the cell periphery. It was hypothesized that the differentiation process is also associated with changes of nuclear organization. The aim of this study was to determine the number and distribution of selected components of nuclear architecture during porcine in vitro adipogenesis. The pig is an important animal model sharing many similarities to humans at the anatomical, physiological, and genetic levels and has been recognized as a good model for human obesity. Thus, understanding how cellular structures important for fundamental nuclear processes may be altered during adipocyte differentiation is of great importance. Mesenchymal stem cells (MSCs) were derived from bone marrow (BM-MSCs) and adipose tissue (AD-MSCs) and were cultured for 7 days in the adipogenic medium. A variable differentiation potential of these cell populations towards adipogenic lineage was observed, and for further study, a comparative characteristic of the nuclear organization in BM-MSCs and AD-MSCs was performed. Nuclear substructures were visualized by indirect immunofluorescence (nucleoli, nuclear speckles, PML bodies, lamins, and HP1α) or fluorescence in situ hybridization (telomeres) on fixed cells at 0, 3, 5, and 7 days of differentiation. Comprehensive characterization of these structures, in terms of their number, size, dynamics, and arrangement in three-dimensional space of the nucleus, was performed. It was found that during differentiation of porcine MSCs into adipocytes, changes of nuclear organization occurred and concerned: (1) the nuclear size and shape; (2) reduced lamin A/C expression; and (3) reorganization of chromocenters. Other elements of nuclear architecture such as nucleoli, SC-35 nuclear speckles, and telomeres

Human milk and infant formula can induce in vitro adipocyte differentiation in murine 3T3-L1 preadipocytes.

PubMed

Lyle, R E; Corley, J D; McGehee, R E

1998-11-01

The potential of infant diet to influence fat cell development has largely been examined in clinical studies with conflicting results. In this study, the direct effects of two standard infant formulas, Enfamil and Similac, as well as human milk were examined using a well characterized model of adipocyte differentiation, the 3T3-L1 murine preadipocyte cell line. After exposure to a hormonal regimen of insulin, dexamethasone, and 1-methyl-3-isobutylmethylxanthine, these cells undergo a mitotic expansion phase followed by terminal differentiation. On d 4 of hormonal exposure, greater than 95% of 3T3-L1 cells exhibit the morphologic and biochemical characteristics of mature adipocytes. In this study, cells were exposed to control medium, or control medium supplemented with either 10% Enfamil, 10% Similac, 10% human milk (skim or whole), or the standard hormonal regimen. Oil Red O-detectable lipid accumulation, immunocytochemical cell proliferation assays, and activated expression of adipocyte differentiation-specific mRNAs by Northern blot analysis were used to assess the effects of treatment on adipocyte differentiation. Results from each level of assessment revealed that both Enfamil and human milk were as effective as the standard hormonal regimen at stimulating adipocyte differentiation. In contrast, results from treatment with Similac or human skim milk were indistinguishable from control unstimulated cells. This study, demonstrating that Enfamil and human milk are capable of independently inducing in vitro adipocyte differentiation, suggests that diet during infancy could influence body fat development.

CBX7 gene expression plays a negative role in adipocyte cell growth and differentiation

PubMed Central

Forzati, Floriana; Federico, Antonella; Pallante, Pierlorenzo; Colamaio, Marianna; Esposito, Francesco; Sepe, Romina; Gargiulo, Sara; Luciano, Antonio; Arra, Claudio; Palma, Giuseppe; Bon, Giulia; Bucher, Stefania; Falcioni, Rita; Brunetti, Arturo; Battista, Sabrina; Fedele, Monica; Fusco, Alfredo

2014-01-01

ABSTRACT We have recently generated knockout mice for the Cbx7 gene, coding for a polycomb group protein that is downregulated in human malignant neoplasias. These mice develop liver and lung adenomas and carcinomas, which confirms a tumour suppressor role for CBX7. The CBX7 ability to downregulate CCNE1 expression likely accounts for the phenotype of the Cbx7-null mice. Unexpectedly, Cbx7-knockout mice had a higher fat tissue mass than wild-type, suggesting a role of CBX7 in adipogenesis. Consistently, we demonstrate that Cbx7-null mouse embryonic fibroblasts go towards adipocyte differentiation more efficiently than their wild-type counterparts, and this effect is Cbx7 dose-dependent. Similar results were obtained when Cbx7-null embryonic stem cells were induced to differentiate into adipocytes. Conversely, mouse embryonic fibroblasts and human adipose-derived stem cells overexpressing CBX7 show an opposite behaviour. These findings support a negative role of CBX7 in the control of adipocyte cell growth and differentiation. PMID:25190058

Development of a rapid culture method to induce adipocyte differentiation of human bone marrow-derived mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ninomiya, Yuichi; Sugahara-Yamashita, Yzumi; Nakachi, Yutaka

2010-04-02

Human mesenchymal stem cells (hMSCs) derived from bone marrow are multipotent stem cells that can regenerate mesenchymal tissues such as adipose, bone or muscle. It is thought that hMSCs can be utilized as a cell resource for tissue engineering and as human models to study cell differentiation mechanisms, such as adipogenesis, osteoblastogenesis and so on. Since it takes 2-3 weeks for hMSCs to differentiate into adipocytes using conventional culture methods, the development of methods to induce faster differentiation into adipocytes is required. In this study we optimized the culture conditions for adipocyte induction to achieve a shorter cultivation time formore » the induction of adipocyte differentiation in bone marrow-derived hMSCs. Briefly, we used a cocktail of dexamethasone, insulin, methylisobutylxanthine (DIM) plus a peroxisome proliferator-activated receptor {gamma} agonist, rosiglitazone (DIMRo) as a new adipogenic differentiation medium. We successfully shortened the period of cultivation to 7-8 days from 2-3 weeks. We also found that rosiglitazone alone was unable to induce adipocyte differentiation from hMSCs in vitro. However, rosiglitazone appears to enhance hMSC adipogenesis in the presence of other hormones and/or compounds, such as DIM. Furthermore, the inhibitory activity of TGF-{beta}1 on adipogenesis could be investigated using DIMRo-treated hMSCs. We conclude that our rapid new culture method is very useful in measuring the effect of molecules that affect adipogenesis in hMSCs.« less

Effects of insulin, triiodothyronine and fat soluble vitamins on adipocyte differentiation and LPL gene expression in the stromal-vascular cells of red sea bream, Pagrus major.

PubMed

Oku, Hiromi; Tokuda, Masaharu; Okumura, Takuji; Umino, Tetsuya

2006-07-01

Various kinds of hormones including insulin, triiodothyronine (T(3)) and fat-soluble vitamins have been proposed as mediators of adipocyte differentiation in mammals. To investigate the factors which are responsible for fish adipocyte differentiation, we developed a serum-free culture system of stromal-vascular cells of red sea bream adipose tissue and examined the effects of bovine insulin, T(3), and fat-soluble vitamins (all-trans retinoic acid, retinyl acetate and 1,25-dihydroxyvitamin D(3)) on the differentiation-linked expression of the lipoprotein lipase (LPL) gene. As assessed by the increase in LPL gene expression after 3 day cultivation, like in mammalian adipocytes, insulin enhanced the adipocyte differentiation in a concentration-dependent manner. During 2 week cultivation, bovine insulin promoted lipid accumulation in differentiating adipocytes concentration-dependently until the terminal differentiation. These results indicate that the differentiation of fish adipocytes is inducible by insulin alone. T(3) alone had no effect but enhanced the differentiation-linked LPL gene expression in the presence of insulin. Fat-soluble vitamins, unlike in mammalian adipocytes, did not show any significant effects. The method developed in this study should be of interest for the characterization of factors involved in fish adipocyte differentiation.

MicroRNA-24 promotes 3T3-L1 adipocyte differentiation by directly targeting the MAPK7 signaling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jin, Min, E-mail: min_jin@zju.edu.cn; Wu, Yutao; Wang, Jing

Over the past years, MicroRNAs (miRNAs) act as a vital role in harmony with gene regulation and maintaining cellular homeostasis. It is well testified that miRNAshave been involved in numerous physiological and pathological processes, including embryogenesis, cell fate decision, and cellular differentiation. Adipogenesis is an organized process of cellular differentiation by which pre-adipocytes differentiate towards mature adipocytes, and it is tightly modulated by a series of transcription factors such as peroxisome proliferator-activated receptor γ (PPAR-γ) and sterol regulatory-element binding proteins 1 (SREBP1). However, the molecular mechanisms underlying the connection between miRNAs and adipogenesis-related transcription factors remain obscure. In this study,more » we unveiled that miR- 24 was remarkably upregulated during 3T3-L1 adipogenesis. Overexpression of miR-24 significantly promoted 3T3-L1 adipogenesis, as evidenced by its ability to increase the expression of PPAR-γ and SREBP1, lipid droplet formation and triglyceride (TG) accumulation. Furthermore, we found that neither ectopic expression of miR-24nor miR-24 inhibitor affect cell proliferation and cell cycle progression. Finally, we demonstrated that miR-24 plays the modulational role by directly repressing MAPK7, a key number in the MAPK signaling pathway. These data indicate that miR-24 is a novel positive regulator of adipocyte differentiation by targeting MAPK7, which provides new insights into the molecular mechanism of miRNA-mediated cellular differentiation. -- Highlights: •We firstly found miR-24 was upregulated in 3T3-L1 pre-adipocytes differentiation. •miR-24 promoted 3T3-L1 pre-adipocytes differentiation while silencing the expression of miR-24 had an opposite function. •miR-24 regulated 3T3-L1 differentiation by directly targeting MAPK7 signaling pathway. •miR-24did not affect 3T3-L1 pre-adipocytes cellular proliferation.« less

Effect of Wnt-1 inducible signaling pathway protein-2 (WISP-2/CCN5), a downstream protein of Wnt signaling, on adipocyte differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inadera, Hidekuni; Shimomura, Akiko; Tachibana, Shinjiro

2009-02-20

Wnt signaling negatively regulates adipocyte differentiation, and ectopic expression of Wnt-1 in 3T3-L1 cells induces several downstream molecules of Wnt signaling, including Wnt-1 inducible signaling pathway protein (WISP)-2. In this study, we examined the role of WISP-2 in the process of adipocyte differentiation using an in vitro cell culture system. In the differentiation of 3T3-L1 cells, WISP-2 expression was observed in growing cells and declined thereafter. In the mitotic clonal expansion phase of adipocyte differentiation, WISP-2 expression was transiently down-regulated concurrently with up-regulation of CCAAT/enhancer-binding protein {delta} expression. Treatment of 3T3-L1 cells in the differentiation medium with lithium, an activatormore » of Wnt signaling, inhibited the differentiation process with concomitant induction of WISP-2. Treatment of differentiated cells with lithium induced de-differentiation as evidenced by profound reduction of peroxisome proliferator-activator receptor {gamma} expression and concomitant induction of WISP-2. However, de-differentiation of differentiated cells induced by tumor necrosis factor-{alpha} did not induce WISP-2 expression. To directly examine the effect of WISP-2 on adipocyte differentiation, 3T3-L1 cells were infected with a retrovirus carrying WISP-2. Although forced expression of WISP-2 inhibited preadipocyte proliferation, it had no effect on adipocyte differentiation. Thus, although WISP-2 is a downstream protein of Wnt signaling, the role of WISP-2 on adipocyte differentiation may be marginal, at least in this in vitro culture model.« less

C-terminus of HSC70-Interacting Protein (CHIP) Inhibits Adipocyte Differentiation via Ubiquitin- and Proteasome-Mediated Degradation of PPARγ

PubMed Central

Kim, Jung-Hoon; Shin, Soyeon; Seo, Jinho; Lee, Eun-Woo; Jeong, Manhyung; Lee, Min-sik; Han, Hyun-Ji; Song, Jaewhan

2017-01-01

PPARγ (Peroxisome proliferator-activated receptor γ) is a nuclear receptor involved in lipid homeostasis and related metabolic diseases. Acting as a transcription factor, PPARγ is a master regulator for adipocyte differentiation. Here, we reveal that CHIP (C-terminus of HSC70-interacting protein) suppresses adipocyte differentiation by functioning as an E3 ligase of PPARγ. CHIP directly binds to and induces ubiquitylation of the PPARγ protein, leading to proteasome-dependent degradation. Stable overexpression or knockdown of CHIP inhibited or promoted adipogenesis, respectively, in 3T3-L1 cells. On the other hand, a CHIP mutant defective in E3 ligase could neither regulate PPARγ protein levels nor suppress adipogenesis, indicating the importance of CHIP-mediated ubiquitylation of PPARγ in adipocyte differentiation. Lastly, a CHIP null embryo fibroblast exhibited augmented adipocyte differentiation with increases in PPARγ and its target protein levels. In conclusion, CHIP acts as an E3 ligase of PPARγ, suppressing PPARγ-mediated adipogenesis. PMID:28059128

GSK126 alleviates the obesity phenotype by promoting the differentiation of thermogenic beige adipocytes in diet-induced obese mice.

PubMed

Wu, Xiaohui; Wang, Yuying; Wang, Yingmei; Wang, Xinli; Li, Jianqiang; Chang, Kaixuan; Sun, Cheng; Jia, Zhen; Gao, Song; Wei, Jiachang; Xu, Jiuhang; Xu, Yuqiao; Li, Qing

2018-06-18

A close relationship between epigenetic regulation and obesity has been demonstrated in several recent studies. Histone methyltransferase enhancer of Zeste homolog 2 (Ezh2), which mainly catalyzes trimethylation of histone H3K27 to form H3K27me3 was found to be required for the differentiation of white and brown adipocytes in vitro. Here, we investigated the effects of the Ezh2-specific inhibitor GSK126 in a mouse model of obesity induced by a high-fat diet (HFD). We found that GSK126 treatment reduced body fat, improved glucose tolerance, increased lipolysis and improved cold tolerance in mice by promoting the differentiation of thermogenic beige adipocytes. Moreover, we discovered that GSK126 inhibited the differentiation of white adipocytes, and the decrease of Ezh2 enzymatic activity and H3K27me3 also changed the morphology of brown adipocytes but did not alter the expression of thermogenic genes in these cells. Our results indicated that GSK126 was a novel chemical inducer of beige adipocytes and may be a potential therapeutic agent for the management of obesity. Furthermore, they also prompted that Ezh2 and H3K27me3 play different roles in the differentiation of the white, brown, and beige adipocytes in vivo. Copyright © 2018 Elsevier Inc. All rights reserved.

Role of fibroblast growth factor receptors (FGFR) and FGFR like-1 (FGFRL1) in mesenchymal stromal cell differentiation to osteoblasts and adipocytes.

PubMed

Kähkönen, T E; Ivaska, K K; Jiang, M; Büki, K G; Väänänen, H K; Härkönen, P L

2018-02-05

Fibroblast growth factors (FGF) and their receptors (FGFRs) regulate many developmental processes including differentiation of mesenchymal stromal cells (MSC). We developed two MSC lines capable of differentiating to osteoblasts and adipocytes and studied the role of FGFRs in this process. We identified FGFR2 and fibroblast growth factor receptor like-1 (FGFRL1) as possible actors in MSC differentiation with gene microarray and qRT-PCR. FGFR2 and FGFRL1 mRNA expression strongly increased during MSC differentiation to osteoblasts. FGF2 treatment, resulting in downregulation of FGFR2, or silencing FGFR2 expression with siRNAs inhibited osteoblast differentiation. During adipocyte differentiation expression of FGFR1 and FGFRL1 increased and was down-regulated by FGF2. FGFR1 knockdown inhibited adipocyte differentiation. Silencing FGFR2 and FGFR1 in MSCs was associated with decreased FGFRL1 expression in osteoblasts and adipocytes, respectively. Our results suggest that FGFR1 and FGFR2 regulate FGFRL1 expression. FGFRL1 may mediate or modulate FGFR regulation of MSC differentiation together with FGFR2 in osteoblastic and FGFR1 in adipocytic lineage. Copyright © 2017 Elsevier B.V. All rights reserved.

Phloretin enhances adipocyte differentiation and adiponectin expression in 3T3-L1 cells.

PubMed

Hassan, Meryl; El Yazidi, Claire; Landrier, Jean-François; Lairon, Denis; Margotat, Alain; Amiot, Marie-Josèphe

2007-09-14

Adipocyte dysfunction is strongly associated with the development of cardiovascular risk factors and diabetes. It is accepted that the regulation of adipogenesis or adipokines expression, notably adiponectin, is able to prevent these disorders. In this report, we show that phloretin, a dietary flavonoid, enhances 3T3-L1 adipocyte differentiation as evidenced by increased triglyceride accumulation and GPDH activity. At a molecular level, mRNA expression levels of both PPARgamma and C/EBPalpha, the master adipogenic transcription factors, are markedly increased by phloretin. Moreover, mRNA levels of PPARgamma target genes such as LPL, aP2, CD36 and LXRalpha are up-regulated by phloretin. We also show that phloretin enhances the expression and secretion of adiponectin. Co-transfection studies suggest the induction of PPARgamma transcriptional activity as a possible mechanism underlying the phloretin-mediated effects. Taken together, these results suggest that phloretin may be beneficial for reducing insulin resistance through its potency to regulate adipocyte differentiation and function.

Multiple intracellular signaling pathways orchestrate adipocytic differentiation of human bone marrow stromal stem cells.

PubMed

Ali, Dalia; Abuelreich, Sarah; Alkeraishan, Nora; Shwish, Najla Bin; Hamam, Rimi; Kassem, Moustapha; Alfayez, Musaad; Aldahmash, Abdullah; Alajez, Nehad M

2018-02-28

Bone marrow adipocyte formation plays a role in bone homeostasis and whole body energy metabolism. However, the transcriptional landscape and signaling pathways associated with adipocyte lineage commitment and maturation are not fully delineated. Thus, we performed global gene expression profiling during adipocyte differentiation of human bone marrow stromal (mesenchymal) stem cells (hMSCs) and identified 2,589 up-regulated and 2,583 down-regulated mRNA transcripts. Pathway analysis on the up-regulated gene list untraveled enrichment in multiple signaling pathways including insulin receptor signaling, focal Adhesion, metapathway biotransformation, a number of metabolic pathways e.g. selenium metabolism, Benzo(a)pyrene metabolism, fatty acid, triacylglycerol, ketone body metabolism, tryptophan metabolism, and catalytic cycle of mammalian flavin-containing monooxygenase (FMOs). On the other hand, pathway analysis on the down-regulated genes revealed significant enrichment in pathways related to cell cycle regulation. Based on these data, we assessed the effect of pharmacological inhibition of FAK signaling using PF-573228, PF-562271, and InsR/IGF-1R using NVP-AEW541 and GSK-1904529A on adipocyte differentiation. hMSCs exposed to FAK or IGF-1R/InsR inhibitors exhibited fewer adipocyte formation (27-58% inhibition, P <0005). Concordantly, the expression of adipocyte-specific genes AP2, AdipoQ, and CEBPα was significantly reduced. On the other hand, we did not detect significant effects on cell viability as a result of FAK or IGF-1R/InsR inhibition. Our data identified FAK and insulin signaling as important intracellular signaling pathways relevant to bone marrow adipogenesis. © 2018 The Author(s).

Epigenetic Library Screen Identifies Abexinostat as Novel Regulator of Adipocytic and Osteoblastic Differentiation of Human Skeletal (Mesenchymal) Stem Cells

PubMed Central

Ali, Dalia; Hamam, Rimi; Alfayez, Musaed; Kassem, Moustapha; Aldahmash, Abdullah

2016-01-01

The epigenetic mechanisms promoting lineage-specific commitment of human skeletal (mesenchymal or stromal) stem cells (hMSCs) into adipocytes or osteoblasts are still not fully understood. Herein, we performed an epigenetic library functional screen and identified several novel compounds, including abexinostat, which promoted adipocytic and osteoblastic differentiation of hMSCs. Using gene expression microarrays, chromatin immunoprecipitation for H3K9Ac combined with high-throughput DNA sequencing (ChIP-seq), and bioinformatics, we identified several key genes involved in regulating stem cell proliferation and differentiation that were targeted by abexinostat. Concordantly, ChIP-quantitative polymerase chain reaction revealed marked increase in H3K9Ac epigenetic mark on the promoter region of AdipoQ, FABP4, PPARγ, KLF15, CEBPA, SP7, and ALPL in abexinostat-treated hMSCs. Pharmacological inhibition of focal adhesion kinase (PF-573228) or insulin-like growth factor-1R/insulin receptor (NVP-AEW51) signaling exhibited significant inhibition of abexinostat-mediated adipocytic differentiation, whereas inhibition of WNT (XAV939) or transforming growth factor-β (SB505124) signaling abrogated abexinostat-mediated osteogenic differentiation of hMSCs. Our findings provide insight into the understanding of the relationship between the epigenetic effect of histone deacetylase inhibitors, transcription factors, and differentiation pathways governing adipocyte and osteoblast differentiation. Manipulating such pathways allows a novel use for epigenetic compounds in hMSC-based therapies and tissue engineering. Significance This unbiased epigenetic library functional screen identified several novel compounds, including abexinostat, that promoted adipocytic and osteoblastic differentiation of human skeletal (mesenchymal or stromal) stem cells (hMSCs). These data provide new insight into the understanding of the relationship between the epigenetic effect of histone deacetylase

Adipocyte differentiation influences the proliferation and migration of normal and tumoral breast epithelial cells.

PubMed

Creydt, Virginia Pistone; Sacca, Paula Alejandra; Tesone, Amelia Julieta; Vidal, Luciano; Calvo, Juan Carlos

2010-01-01

Stromal tissue regulates the development and differentiation of breast epithelial cells, with adipocytes being the main stromal cell type. The aim of the present study was to evaluate the effect of adipocyte differentiation on proliferation and migration, as well as to assess the activity of heparanase and metalloproteinase-9 (MMP-9), in normal (NMuMG) and tumoral (LM3) murine breast epithelial cells. NMuMG and LM3 cells were grown on irradiated 3T3-L1 cells (stromal support, SS) at various degrees of differentiation [preadipocytes (preA), poorly differentiated adipocytes (pDA) and mature adipocytes (MA)] and/or were incubated in the presence of conditioned medium (CM) derived from each of these three types of differentiated cells. Cells grown on a plastic support or in fresh medium served as the controls. Cell proliferation was measured with a commercial colorimetric kit, and the motility of the epithelial cells was evaluated by means of a wound-healing assay. Heparanase activity was assessed by quantifying heparin degradation, and the expression of MMP-9 was determined using Western blotting. The results indicate that cell proliferation was increased after 24 and 48 h in the NMuMG and LM3 cells grown on preA, pDA and MA SS. In the NMuMG cells cultured on SS in the presence of all three types of CM, proliferation was enhanced. LM3 cell migration was increased in the presence of all three types of CM and in cells grown on preA SS. Heparanase activity was increased in the NMuMG cells incubated with all three types of CM, and in the LM3 cells incubated with the CM from pDA and MA. Both the NMuMG and LM3 cell lines presented basal expression of MMP-9; however, a significant increase in MMP-9 expression was observed in the LM3 cells incubated with each of the three types of CM. In conclusion, adipocyte differentiation influences normal and tumoral breast epithelial cell proliferation and migration. Heparanase and MMP-9 appear to be involved in this regulation. The

Developmental Programming: Impact of Prenatal Testosterone Excess on Steroidal Machinery and Cell Differentiation Markers in Visceral Adipocytes of Female Sheep.

PubMed

Puttabyatappa, Muraly; Lu, Chunxia; Martin, Jacob D; Chazenbalk, Gregorio; Dumesic, Daniel; Padmanabhan, Vasantha

2017-01-01

Prenatal testosterone (T)-treated female sheep manifest reduced adipocyte size and peripheral insulin resistance. The small adipocyte phenotype may reflect defects in adipogenesis and its steroidal machinery. To test whether prenatal T treatment from gestational days 30 to 90 alters the visceral adipose tissue (VAT) steroidal machinery and reduces adipocyte differentiation, we examined expression of the steroidogenic enzymes, steroid receptors, and adipocyte differentiation markers at fetal day 90 and postnatal ages 10 and 21 months. Because gestational T treatment increases fetal T and maternal insulin, the contributions of these were assessed by androgen receptor antagonist or insulin sensitizer cotreatment, either separately (at fetal day 90 and 21 months of age time points) or together (10 months of age). The effects on adipogenesis were assessed in the VAT-derived mesenchymal stem cells (AT-MSCs) from pre- and postpubertal time points to evaluate the effects of pubertal steroidal changes on adipogenesis. Our results show that VAT manifests potentially a predominant estrogenic intracrine milieu (increased aromatase and estrogen receptor α) and reduced differentiation markers at fetal day 90 and postnatal 21 months of age. These changes appear to involve both androgenic and metabolic pathways. Preliminary findings suggest that prenatal T treatment reduces adipogenesis, decreases expression of differentiation, and increases expression of commitment markers at both pre- and postpubertal time points. Together, these findings suggest that (1) increased commitment of AT-MSCs to adipocyte lineage and decreased differentiation to adipocytes may underlie the small adipocyte phenotype of prenatal T-treated females and (2) excess T-induced changes in steroidal machinery in the VAT likely participate in the programming/maintenance of this defect.

Factor for adipocyte differentiation 158 gene disruption prevents the body weight gain and insulin resistance induced by a high-fat diet.

PubMed

Hayashi, Takahiro; Nozaki, Yuriko; Nishizuka, Makoto; Ikawa, Masahito; Osada, Shigehiro; Imagawa, Masayoshi

2011-01-01

To clarify the molecular mechanism of adipocyte differentiation, we previously isolated a novel gene, factor for adipocyte differentiation (fad) 158, whose expression was induced during the earliest stages of adipogenesis, and its product was localized to the endoplasmic reticulum. We found that the knockdown of fad158 expression prevented the differentiation of 3T3-L1 cells into adipocytes. In addition, over-expression of fad158 promoted the differentiation of NIH-3T3 cells, which do not usually differentiate into adipocytes. Although these findings strongly suggest that fad158 has a crucial role in regulating adipocyte differentiation, the physiological role of the gene is still unclear. In this study, we generated mice in which fad158 expression was deleted. The fad158-deficient mice did not show remarkable changes in body weight or the weight of white adipose tissue on a chow diet, but had significantly lower body weights and fat mass than wild-type mice when fed a high-fat diet. Furthermore, although the disruption of fad158 did not influence insulin sensitivity on the chow diet, it improved insulin resistance induced by the high-fat diet. These results indicate that fad158 is a key factor in the development of obesity and insulin resistance caused by a high-fat diet.

Organotins Are Potent Activators of PPARγ and Adipocyte Differentiation in Bone Marrow Multipotent Mesenchymal Stromal Cells

PubMed Central

Yanik, Susan C.; Baker, Amelia H.; Mann, Koren K.; Schlezinger, Jennifer J.

2011-01-01

Adipocyte differentiation in bone marrow is potentially deleterious to both bone integrity and lymphopoiesis. Here, we examine the hypothesis that organotins, common environmental contaminants that are dual ligands for peroxisome proliferator–activated receptor (PPAR) γ and its heterodimerization partner retinoid X receptor (RXR), are potent activators of bone marrow adipogenesis. A C57Bl/6-derived bone marrow multipotent mesenchymal stromal cell (MSC) line, BMS2, was treated with rosiglitazone, a PPARγ agonist, bexarotene, an RXR agonist, or a series of organotins. Rosiglitazone and bexarotene potently activated adipocyte differentiation; however, bexarotene had a maximal efficacy of only 20% of that induced by rosiglitazone. Organotins (tributyltin [TBT], triphenyltin, and dibutyltin) also stimulated adipocyte differentiation (EC50 of 10–20nM) but with submaximal, structure-dependent efficacy. In coexposures, both bexarotene and TBT enhanced rosiglitazone-induced adipogenesis. To investigate the contribution of PPARγ to TBT-induced adipogenesis, we examined expression of PPARγ2, as well as its transcriptional target FABP4. TBT-induced PPARγ2 and FABP4 protein expression with an efficacy intermediate between rosiglitazone and bexarotene, similar to lipid accumulation. A PPARγ antagonist and PPARγ-specific small hairpin RNA suppressed TBT-induced differentiation, although to a lesser extent than rosiglitazone-induced differentiation, suggesting that TBT may engage alternate pathways. TBT and bexarotene, but not rosiglitazone, also induced the expression of TGM2 (an RXR target) and ABCA1 (a liver X receptor target). The results show that an environmental contaminant, acting with the same potency as a therapeutic drug, induces PPARγ-dependent adipocyte differentiation in bone marrow MSCs. Activation of multiple nuclear receptor pathways by organotins may have significant implications for bone physiology. PMID:21622945

Interaction of differentiated human adipocytes with macrophages leads to trogocytosis and selective IL-6 secretion

PubMed Central

Sárvári, A K; Doan-Xuan, Q-M; Bacsó, Z; Csomós, I; Balajthy, Z; Fésüs, L

2015-01-01

Obesity leads to adipose tissue inflammation that is characterized by increased release of proinflammatory molecules and the recruitment of activated immune cells. Although macrophages are present in the highest number among the immune cells in obese adipose tissue, not much is known about their direct interaction with adipocytes. We have introduced an ex vivo experimental system to characterize the cellular interactions and the profile of secreted cytokines in cocultures of macrophages and human adipocytes differentiated from either mesenchymal stem cells or a preadipocyte cell line. As observed by time-lapse microscopy, flow, and laser-scanning cytometry, macrophages phagocytosed bites of adipocytes (trogocytosis), which led to their de novo, phagocytosis and NF-κB-dependent synthesis, then release of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1. IL-6 secretion was not accompanied by secretion of other proinflammatory cytokines, such as tumor necrosis factor (TNF)-α and IL-8, except MCP-1. LPS-induced release of TNF-α, IL-8 and MCP-1 was decreased in the presence of the differentiated adipocytes but the IL-6 level did not subside suggesting that phagocytosis-dependent IL-6 secretion may have significant regulatory function in the inflamed adipose tissue. PMID:25611388

Interaction of differentiated human adipocytes with macrophages leads to trogocytosis and selective IL-6 secretion.

PubMed

Sárvári, A K; Doan-Xuan, Q-M; Bacsó, Z; Csomós, I; Balajthy, Z; Fésüs, L

2015-01-22

Obesity leads to adipose tissue inflammation that is characterized by increased release of proinflammatory molecules and the recruitment of activated immune cells. Although macrophages are present in the highest number among the immune cells in obese adipose tissue, not much is known about their direct interaction with adipocytes. We have introduced an ex vivo experimental system to characterize the cellular interactions and the profile of secreted cytokines in cocultures of macrophages and human adipocytes differentiated from either mesenchymal stem cells or a preadipocyte cell line. As observed by time-lapse microscopy, flow, and laser-scanning cytometry, macrophages phagocytosed bites of adipocytes (trogocytosis), which led to their de novo, phagocytosis and NF-κB-dependent synthesis, then release of interleukin (IL)-6 and monocyte chemoattractant protein (MCP)-1. IL-6 secretion was not accompanied by secretion of other proinflammatory cytokines, such as tumor necrosis factor (TNF)-α and IL-8, except MCP-1. LPS-induced release of TNF-α, IL-8 and MCP-1 was decreased in the presence of the differentiated adipocytes but the IL-6 level did not subside suggesting that phagocytosis-dependent IL-6 secretion may have significant regulatory function in the inflamed adipose tissue.

Global Mapping of Cell Type–Specific Open Chromatin by FAIRE-seq Reveals the Regulatory Role of the NFI Family in Adipocyte Differentiation

PubMed Central

Yu, Jing; Hirose-Yotsuya, Lisa; Take, Kazumi; Sun, Wei; Iwabu, Masato; Okada-Iwabu, Miki; Fujita, Takanori; Aoyama, Tomohisa; Tsutsumi, Shuichi; Ueki, Kohjiro; Kodama, Tatsuhiko; Sakai, Juro; Aburatani, Hiroyuki; Kadowaki, Takashi

2011-01-01

Identification of regulatory elements within the genome is crucial for understanding the mechanisms that govern cell type–specific gene expression. We generated genome-wide maps of open chromatin sites in 3T3-L1 adipocytes (on day 0 and day 8 of differentiation) and NIH-3T3 fibroblasts using formaldehyde-assisted isolation of regulatory elements coupled with high-throughput sequencing (FAIRE-seq). FAIRE peaks at the promoter were associated with active transcription and histone modifications of H3K4me3 and H3K27ac. Non-promoter FAIRE peaks were characterized by H3K4me1+/me3-, the signature of enhancers, and were largely located in distal regions. The non-promoter FAIRE peaks showed dynamic change during differentiation, while the promoter FAIRE peaks were relatively constant. Functionally, the adipocyte- and preadipocyte-specific non-promoter FAIRE peaks were, respectively, associated with genes up-regulated and down-regulated by differentiation. Genes highly up-regulated during differentiation were associated with multiple clustered adipocyte-specific FAIRE peaks. Among the adipocyte-specific FAIRE peaks, 45.3% and 11.7% overlapped binding sites for, respectively, PPARγ and C/EBPα, the master regulators of adipocyte differentiation. Computational motif analyses of the adipocyte-specific FAIRE peaks revealed enrichment of a binding motif for nuclear family I (NFI) transcription factors. Indeed, ChIP assay showed that NFI occupy the adipocyte-specific FAIRE peaks and/or the PPARγ binding sites near PPARγ, C/EBPα, and aP2 genes. Overexpression of NFIA in 3T3-L1 cells resulted in robust induction of these genes and lipid droplet formation without differentiation stimulus. Overexpression of dominant-negative NFIA or siRNA–mediated knockdown of NFIA or NFIB significantly suppressed both induction of genes and lipid accumulation during differentiation, suggesting a physiological function of these factors in the adipogenic program. Together, our study

Saw palmetto ethanol extract inhibits adipocyte differentiation.

PubMed

Villaverde, Nicole; Galvis, Adriana; Marcano, Adriana; Priestap, Horacio A; Bennett, Bradley C; Barbieri, M Alejandro

2013-07-01

The fruits of saw palmetto have been used for the treatment of a variety of urinary and reproductive system problems. In this study we investigated whether the fruit extracts affect in vitro adipogenesis. Saw palmetto ethanol extract inhibited the lipid droplet accumulation by induction media in a dose-dependent manner, and it also attenuated the protein expressions of C-EBPα and PPARγ. Phosphorylation of Erk1/2 and Akt1 were also decreased by saw palmetto ethanol extract. This report suggests that saw palmetto extracts selectively affect the adipocyte differentiation through the modulation of several key factors that play a critical role during adipogenesis.

Aculeatin, a coumarin derived from Toddalia asiatica (L.) Lam., enhances differentiation and lipolysis of 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watanabe, Akio, E-mail: watanabea@jfrl.or.jp; Food and Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Miyagi 981-8555; Kato, Tsuyoshi

Highlights: • Aculeatin promoted adipocyte differentiation. • Aculeatin improved glucose uptake. • Aculeatin enhanced adipocyte lipolysis. - Abstract: Toddalia asiatica (L.) Lam. (T. asiatica) has been utilized traditionally for medicinal purposes such as the treatment of diabetes. Currently, the extract is considered to be a good source of anti-diabetic agents, but the active compounds have yet to be identified. In this study, we investigated the effects of fractionated T. asiatica extracts on the differentiation of 3T3-L1 preadipocytes and identified aculeatin as a potential active agent. When 3T3-L1 preadipocytes were treated with aculeatin isolated from T. asiatica in the presence ofmore » insulin, aculeatin increased cellular triglyceride levels and glycerol-3-phosphate dehydrogenase activity. This indicated that aculeatin could enhance the differentiation of preadipocytes into adipocytes. Further analyses using a DNA microarray and real-time quantitative reverse-transcription PCR showed an increase in the expression of peroxisome proliferator-activated receptor-γ target genes (Pparg, Ap2, Cd36, Glut4 and Adipoq) by aculeatin, suggesting that aculeatin enhances the differentiation of 3T3-L1 cells by modulating the expression of genes critical for adipogenesis. Interestingly, after treatment of differentiated adipocytes with aculeatin, glucose uptake and lipolysis were enhanced. Overall, our results suggested that aculeatin is an active compound in T. asiatica for enhancing both differentiation and lipolysis of adipocytes, which are useful for the treatment of lipid abnormalities as well as diabetes.« less

Phloretin promotes adipocyte differentiation in vitro and improves glucose homeostasis in vivo

USDA-ARS?s Scientific Manuscript database

Adipocyte dysfunction is associated with many metabolic diseases such as obesity, insulin resistance and diabetes. Previous studies found that phloretin promotes 3T3-L1 cells differentiation, but the underlying mechanisms for phloretin's effects on adipogenesis remain unclear. In this study, we demo...

Glucose availability controls adipogenesis in mouse 3T3-L1 adipocytes via up-regulation of nicotinamide metabolism.

PubMed

Jackson, Robert M; Griesel, Beth A; Gurley, Jami M; Szweda, Luke I; Olson, Ann Louise

2017-11-10

Expansion of adipose tissue in response to a positive energy balance underlies obesity and occurs through both hypertrophy of existing cells and increased differentiation of adipocyte precursors (hyperplasia). To better understand the nutrient signals that promote adipocyte differentiation, we investigated the role of glucose availability in regulating adipocyte differentiation and maturation. 3T3-L1 preadipocytes were grown and differentiated in medium containing a standard differentiation hormone mixture and either 4 or 25 mm glucose. Adipocyte maturation at day 9 post-differentiation was determined by key adipocyte markers, including glucose transporter 4 (GLUT4) and adiponectin expression and Oil Red O staining of neutral lipids. We found that adipocyte differentiation and maturation required a pulse of 25 mm glucose only during the first 3 days of differentiation. Importantly, fatty acids were unable to substitute for the 25 mm glucose pulse during this period. The 25 mm glucose pulse increased adiponectin and GLUT4 expression and accumulation of neutral lipids via distinct mechanisms. Adiponectin expression and other early markers of differentiation required an increase in the intracellular pool of total NAD/P. In contrast, GLUT4 protein expression was only partially restored by increased NAD/P levels. Furthermore, GLUT4 mRNA expression was mediated by glucose-dependent activation of GLUT4 gene transcription through the cis-acting GLUT4-liver X receptor element (LXRE) promoter element. In summary, this study supports the conclusion that high glucose promotes adipocyte differentiation via distinct metabolic pathways and independently of fatty acids. This may partly explain the mechanism underlying adipocyte hyperplasia that occurs much later than adipocyte hypertrophy in the development of obesity. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

CDK5 Regulatory Subunit-Associated Protein 1-like 1 Negatively Regulates Adipocyte Differentiation through Activation of Wnt Signaling Pathway.

PubMed

Take, Kazumi; Waki, Hironori; Sun, Wei; Wada, Takahito; Yu, Jing; Nakamura, Masahiro; Aoyama, Tomohisa; Yamauchi, Toshimasa; Kadowaki, Takashi

2017-08-04

CDK5 Regulatory Subunit-Associated Protein 1-like 1 (CDKAL1) was identified as a susceptibility gene for type 2 diabetes and body mass index in genome-wide association studies. Although it was reported that CDKAL1 is a methylthiotransferase essential for tRNA Lys (UUU) and faithful translation of proinsulin generated in pancreatic β cells, the role of CDKAL1 in adipocytes has not been understood well. In this study, we found that CDKAL1 is expressed in adipose tissue and its expression is increased during differentiation. Stable overexpression of CDKAL1, however, inhibited adipocyte differentiation of 3T3-L1 cells, whereas knockdown of CDKAL1 promoted differentiation. CDKAL1 increased protein levels of β-catenin and its active unphosphorylated form in the nucleus, thereby promoting Wnt target gene expression, suggesting that CDKAL1 activated the Wnt/β-catenin pathway-a well-characterized inhibitory regulator of adipocyte differentiation. Mutant experiments show that conserved cysteine residues of Fe-S clusters of CDKAL1 are essential for its anti-adipogenic action. Our results identify CDKAL1 as novel negative regulator of adipocyte differentiation and provide insights into the link between CDKAL1 and metabolic diseases such as type 2 diabetes and obesity.

Interruptin B induces brown adipocyte differentiation and glucose consumption in adipose-derived stem cells

PubMed Central

KAEWSUWAN, SIREEWAN; PLUBRUKARN, ANUCHIT; UTSINTONG, MALEERUK; KIM, SEOK-HO; JEONG, JIN-HYUN; CHO, JIN GU; PARK, SANG GYU; SUNG, JONG-HYUK

2016-01-01

Interruptin B has been isolated from Cyclosorus terminans, however, its pharamcological effect has not been fully identified. In the present study, the effects of interruptin B, from C. terminans, on brown adipocyte differentiation and glucose uptake in adipose-derived stem cells (ASCs) were investigated. The results revealed that interruptin B dose-dependently enhanced the adipogenic differentiation of ASCs, with an induction in the mRNA expression levels of peroxisome proliferator-activated receptor (PPAR)-α and PPAR-γ. In addition, interruptin B efficiently increased the number and the membrane potential of mitochondria and upregulated the mRNA expression levels of uncoupling protein (UCP)-1 and cyclooxygenase (COX)-2, which are all predominantly expressed in brown adipocytes. Interruptin B increased glucose consumption in differentiated ASCs, accompanied by the upregulation in the mRNA expression levels of glucose transporter (GLUT)-1 and GLUT-4. The computational analysis of molecular docking, a luciferase reporter assay and surface plasmon resonance confirmed the marked binding affinity of interruptin B to PPAR-α and PPAR-γ (KD values of 5.32 and 0.10 µM, respectively). To the best of our knowledge, the present study is the first report to show the stimulatory effects of interruptin B on brown adipocyte differentiation and glucose uptake in ASCs, through its role as a dual PPAR-α and PPAR-γ ligand. Therefore, interruptin B could be further developed as a therapeutic agent for the treatment of diabetes. PMID:26781331

Testosterone regulates 3T3-L1 pre-adipocyte differentiation and epididymal fat accumulation in mice through modulating macrophage polarization.

PubMed

Ren, Xiaojiao; Fu, Xiaojian; Zhang, Xinhua; Chen, Shiqiang; Huang, Shuguang; Yao, Lun; Liu, Guoquan

2017-09-15

Low testosterone levels are strongly related to obesity in males. The balance between the classically M1 and alternatively M2 polarized macrophages also plays a critical role in obesity. It is not clear whether testosterone regulates macrophage polarization and then affects adipocyte differentiation. In this report, we demonstrate that testosterone strengthens interleukin (IL) -4-induced M2 polarization and inhibits lipopolysaccharide (LPS)-induced M1 polarization, but has no direct effect on adipocyte differentiation. Cellular signaling studies indicate that testosterone regulates macrophage polarization through the inhibitory regulative G-protein (Gαi) mainly, rather than via androgen receptors, and phosphorylation of Akt. Moreover, testosterone inhibits pre-adipocyte differentiation induced by M1 macrophage medium. Lowering of serum testosterone in mice by injecting a luteinizing hormone receptor (LHR) peptide increases epididymal white adipose tissue. Testosterone supplementation reverses this effect. Therefore, our findings indicate that testosterone inhibits pre-adipocyte differentiation by switching macrophages to M2 polarization through the Gαi and Akt signaling pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

Isolation and Culture of Pig Spermatogonial Stem Cells and Their in Vitro Differentiation into Neuron-Like Cells and Adipocytes

PubMed Central

Wang, Xiaoyan; Chen, Tingfeng; Zhang, Yani; Li, Bichun; Xu, Qi; Song, Chengyi

2015-01-01

Spermatogonial stem cells (SSCs) renew themselves throughout the life of an organism and also differentiate into sperm in the adult. They are multipopent and therefore, can be induced to differentiate into many cells types in vitro. SSCs from pigs, considered an ideal animal model, are used in studies of male infertility, regenerative medicine, and preparation of transgenic animals. Here, we report on a culture system for porcine SSCs and the differentiation of these cells into neuron-like cells and adipocytes. SSCs and Sertoli cells were isolated from neonatal piglet testis by differential adhesion and SSCs were cultured on a feeder layer of Sertoli cells. Third-generation SSCs were induced to differentiate into neuron-like cells by addition of retinoic acid, β-mercaptoethanol, and 3-isobutyl-1-methylxanthine (IBMX) to the induction media and into adipocytes by the addition of hexadecadrol, insulin, and IBMX to the induction media. The differentiated cells were characterized by biochemical staining, qRT-PCR, and immunocytochemistry. The cells were positive for SSC markers, including alkaline phosphatase and SSC-specific genes, consistent with the cells being undifferentiated. The isolated SSCs survived on the Sertoli cells for 15 generations. Karyotyping confirmed that the chromosomal number of the SSCs were normal for pig (2n = 38, n = 19). Pig SSCs were successfully induced into neuron-like cells eight days after induction and into adipocytes 22 days after induction as determined by biochemical and immunocytochemical staining. qPCR results also support this conclusion. The nervous tissue markers genes, Nestin and β-tubulin, were expressed in the neuron-like cells and the adipocyte marker genes, PPARγ and C/EBPα, were expressed in the adipocytes. PMID:26556335

The lipid fraction of human milk initiates adipocyte differentiation in 3T3-L1 cells.

PubMed

Fujisawa, Yasuko; Yamaguchi, Rie; Nagata, Eiko; Satake, Eiichiro; Sano, Shinichiro; Matsushita, Rie; Kitsuta, Kazunobu; Nakashima, Shinichi; Nakanishi, Toshiki; Nakagawa, Yuichi; Ogata, Tsutomu

2013-09-01

The prevalence of childhood obesity has increased worldwide over the past decade. Despite evidence that human milk lowers the risk of childhood obesity, the mechanism is not fully understood. We investigated the direct effect of human milk on differentiation of 3T3-L1 preadipocytes. 3T3-L1 preadipocytes were treated with donated human milk only or the combination of the standard hormone mixture; insulin, dexamethasone (DEX), and 3-isobututyl-1-methylxanthine (IBMX). Furthermore, the induction of preadipocyte differentiation by extracted lipids from human milk was tested in comparison to the cells treated with lipid extracts from infant formula. Adipocyte differentiation, specific genes as well as formation of lipid droplets were examined. We clearly show that lipids present in human milk initiate 3T3-L1 preadipocyte differentiation. In contrast, this effect was not observed in response to lipids present in infant formula. The initiation of preadipocyte differentiation by human milk was enhanced by adding the adipogenic hormone, DEX or insulin. The expression of late adipocyte markers in Day 7 adipocytes that have been induced into differentiation with human milk lipid extracts was comparable to those in control cells initiated by a standard adipogenic hormone cocktail. These results demonstrate that human milk contains bioactive lipids that can initiate preadipocyte differentiation in the absence of the standard adipogenic compounds via a unique pathway. Copyright © 2013 Elsevier Ltd. All rights reserved.

Bisindoylmaleimide I suppresses adipocyte differentiation through stabilization of intracellular {beta}-catenin protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cho, Munju; Park, Seoyoung; Gwak, Jungsug

2008-02-29

The Wnt/{beta}-catenin signaling pathway plays important roles in cell differentiation. Activation of this pathway, likely by Wnt-10b, has been shown to inhibit adipogenesis in cultured 3T3-L1 preadipocytes and mice. Here we revealed that bisindoylmaleimide I (BIM), which is widely used as a specific inhibitor of protein kinase C (PKC), inhibits adipocyte differentiation through activation of the Wnt/{beta}-catenin signaling pathway. BIM increased {beta}-catenin responsive transcription (CRT) and up-regulated intracellular {beta}-catenin levels in HEK293 cells and 3T3-L1 preadipocytes. BIM significantly decreased intracellular lipid accumulation and reduced expression of important adipocyte marker genes including peroxisome-proliferator-activated receptor {gamma} (PPAR{gamma}) and CAATT enhancer-binding protein {alpha}more » (C/EBP{alpha}) in 3T3-L1 preadipocytes. Taken together, our findings indicate that BIM inhibits adipogenesis by increasing the stability of {beta}-catenin protein in 3T3-L1 preadipocyte cells.« less

Eicosapentaenoic acid and arachidonic acid differentially regulate adipogenesis, acquisition of a brite phenotype and mitochondrial function in primary human adipocytes.

PubMed

Fleckenstein-Elsen, Manuela; Dinnies, Daniela; Jelenik, Tomas; Roden, Michael; Romacho, Tania; Eckel, Jürgen

2016-09-01

n-3 and n-6 PUFAs have several opposing biological effects and influence white adipose tissue (WAT) function. The recent discovery of thermogenic UCP1-expressing brite adipocytes within WAT raised the question whether n-3 and n-6 PUFAs exert differential effects on brite adipocyte formation and mitochondrial function. Primary human preadipocytes were treated with n-3 PUFAs (eicosapentaenoic acid, EPA; docosahexaenoic acid, DHA) or n-6 PUFA (arachidonic acid, ARA) during differentiation, and adipogenesis, white and brite gene expression markers, mitochondrial content and function were analyzed at day 12 of differentiation. Adipogenesis was equally increased by n-3 and n-6 PUFAs. The n-6 PUFA ARA increased lipid droplet size and expression of the white-specific marker TCF21 while decreased mitochondrial protein expression and respiratory function. In contrast, EPA increased expression of the brown adipocyte-related genes UCP1 and CPT1B, and improved mitochondrial function of adipocytes. The opposing effects of EPA and ARA on gene expression and mitochondrial function were also observed in cells treated from day 8 to 12 of adipocyte differentiation. EPA promotes brite adipogenesis and improves parameters of mitochondrial function, such as increased expression of CPTB1, citrate synthase activity and higher maximal respiratory capacity, while ARA reduced mitochondrial spare respiratory capacity in vitro. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

BIX-01294 promotes the differentiation of adipose mesenchymal stem cells into adipocytes and neural cells in Arbas Cashmere goats.

PubMed

Wang, Qing; Wang, Xiao; Lai, Defang; Deng, Jin; Hou, Zhuang; Liang, Hao; Liu, Dongjun

2018-05-14

Chromatin remodeling plays an essential role in regulating gene transcription. BIX-01294 is a specific inhibitor of histone methyltransferase G9a, which is responsible for methylation of histone H3 lysine 9 (H3K9) that can also regulate DNA methylation and chromatin remodeling. The purpose of this study was to investigate the effects of BIX-01294 on the potential of goat adipose derived stem cells (gADSCs) to differentiate into adipocytes and neural cells. To accomplish this, BIX-01294 was used to treat gADSCs for 24 h, and the global level of DNA methylation as well as the expression of genes related to cell proliferation, apoptosis and pluripotency were detected. At the same time, the cells were induced to differentiate into adipocytes and neural cells, and the transcription levels of related marker factors were examined. We found that BIX-01294 treatment reduced the level of DNA methylation and increased the level of gADSCs hydroxylmethylation. The translation level of NANOG increased, whereas Oct4, Sox2 levels decreased. Our results suggest that BIX-01294 may rely on the NANOG regulatory network to promote gADSCs differentiation. We found that both the lipid droplet level in adipocytes and the transcription levels of the adipocyte specific factors Fabp4, ADIPOQ, and Leptin increased after treatment. ENO2 and RBFOX3 transcription levels were also elevated in the differentiated neural cells after treatment. These results indicated that BIX-01294 treatment promoted the differentiation of gADSCs into adipocytes and neural cells. Our findings provide new ideas for improving the differentiation potential of gADSCs and expanding possible application for gADSCs. Copyright © 2018. Published by Elsevier Ltd.

Identification and expression patterns of adipokine genes during adipocyte differentiation in the Tibetan goat (Capra hircus).

PubMed

Li, Xueying; Wang, Yan; Guo, Jiazhong; Zhong, Tao; Li, Li; Zhang, Hongping; Wang, Linjie

2018-02-15

Adipokines are secreted by adipose tissue and play an important role in the regulation of lipid metabolism. However, the information regarding adipokines in goats is limited. PPARγ is a key gene in adipocyte differentiation and activates adipokine genes. Rosiglitazone is a PPARγ agonist and can promote the expression of PPARγ to increase the expression of lipogenesis-related genes. Therefore, investigation of the relationship between rosiglitazone and adipokines will help us to better understand the function of PPARγ in lipid metabolism in Tibetan goats. In this study, we cloned the resistin (RETN), apelin (APLN), fibroblast growth factor 21 (FGF21), and visfatin (NAMPT) genes from non-pregnant female Tibetan goat adipose tissue. APLN and NAMPT were predominantly expressed in the kidney, and FGF21 was expressed at the highest levels in the liver in vivo. In fat tissues, the highest expression levels of FGF21 and RETN were detected in omental fat, whereas their expression in perirenal and subcutaneous fat was extremely weak. APLN and NAMPT were abundantly expressed in omental and subcutaneous fat in vivo. In addition, the four adipokines had different expression profiles during goat adipocyte differentiation in vitro. Oil red O staining showed that rosiglitazone could promote adipocyte differentiation and lipid droplet formation. In addition, rosiglitazone significantly increased the expression of FGF21 and RETN (p<0.05) but decreased the expression of APLN and NAMPT (p<0.05). These results suggest that the four adipocytokine genes may have different roles during goat adipocyte differentiation. And PPARγ could regulate the expression of the four adipokines, but the detailed regulatory mechanism still needs to be elucidated. Copyright © 2017 Elsevier B.V. All rights reserved.

Aristolochia Manshuriensis Kom Inhibits Adipocyte Differentiation by Regulation of ERK1/2 and Akt Pathway

PubMed Central

Kwak, Dong Hoon; Lee, Ji-Hye; Kim, Taesoo; Ahn, Hyo Sun; Cho, Won-Kyung; Ha, Hyunil; Hwang, Youn-Hwan; Ma, Jin Yeul

2012-01-01

Aristolochia manshuriensis Kom (AMK) is a traditional medicinal herb used for the treatment of arthritis, rheumatism, hepatitis, and anti-obesity. Because of nephrotoxicity and carcinogenicity of AMK, there are no pharmacological reports on anti-obesity potential of AMK. Here, we showed AMK has an inhibitory effect on adipocyte differentiation of 3T3-L1 cells along with significantly decrease in the lipid accumulation by downregulating several adipocyte-specific transcription factors including peroxisome proliferation-activity receptor γ (PPAR-γ), CCAAT/enhancer binding protein α (C/EBP-α) and C/EBP-β, which are critical for adipogenesis in vitro. AMK also markedly activated the extracellular signal-regulated protein kinase 1/2 (ERK1/2) pathway including Ras, Raf1, and mitogen-activated protein kinase kinase 1 (MEK1), and significantly suppressed Akt pathway by inhibition of phosphoinositide-dependent kinase 1 (PDK1). Aristolochic acid (AA) and ethyl acetate (EtOAc) fraction of AMK with AA were significantly inhibited TG accumulation, and regulated two pathway (ERK1/2 and Akt) during adipocyte differentiation, and was not due to its cytotoxicity. These two pathways were upstream of PPAR-γ and C/EBPα in the adipogenesis. In addition, gene expressions of secreting factors such as fatty acid synthase (FAS), adiponectin, lipopreotein lipase (LPL), and aP2 were significantly inhibited by treatment of AMK during adipogenesis. We used the high-fat diet (HFD)-induced obesity mouse model to determine the inhibitory effects of AMK on obesity. Oral administration of AMK (62.5 mg/kg/day) significantly decreased the fat tissue weight, total cholesterol (TC), and low density lipoprotein-cholesterol (LDL-C) concentration in the blood. The results of this study suggested that AMK inhibited lipid accumulation by the down-regulation of the major transcription factors of the adipogensis pathway including PPAR-γ and C/EBP-α through regulation of Akt pathway and ERK 1

Phenyl-γ-valerolactones, flavan-3-ol colonic metabolites, protect brown adipocytes from oxidative stress without affecting their differentiation or function.

PubMed

Mele, Laura; Carobbio, Stefania; Brindani, Nicoletta; Curti, Claudio; Rodriguez-Cuenca, Sergio; Bidault, Guillaume; Mena, Pedro; Zanotti, Ilaria; Vacca, Michele; Vidal-Puig, Antonio; Del Rio, Daniele

2017-09-01

Consumption of products rich in flavan-3-ols, such as tea and cocoa, has been associated with decreased obesity, partially dependent on their capacity to enhance energy expenditure. Despite these phenolics having been reported to increase the thermogenic program in brown and white adipose tissue, flavan-3-ols are vastly metabolised in vivo to phenyl-γ-valerolactones. Therefore, we hypothesize that phenyl-γ-valerolactones may directly stimulate the differentiation and the activation of brown adipocytes. Immortalized brown pre-adipocytes were differentiated in presence of (R)-5-(3',4'-dihydroxyphenyl)-γ-valerolactone (VL1), (R)-5-(3´-hydroxyphenyl)-γ-valerolactone-4'-O-sulphate (VL2), (R)-5-phenyl-γ-valerolactone-3´,4´-di-O-sulphate (VL3), at concentrations of 2 or 10μM, whereas fully differentiated brown adipocyte were treated acutely (6-24h). None of the treatments regulated the expression levels of the uncouple protein 1, nor of the main transcription factors involved in brown adipogenesis. Similarly, mitochondrial content was unchanged after treatments. Moreover these compounds did not display peroxisome proliferator-activated receptor γ-agonist activity, as evaluated by luciferase assay, and did not enhance norepinephrine-stimulated lipolysis in mature adipocytes. However, both VL1 and VL2 prevented oxidative stress caused by H 2 O 2 . Phenyl-γ-valerolactones and their sulphated forms do not influence brown adipocyte development or function at physiological or supraphysiological doses in vitro, but they are active protecting brown adipocytes from increased reactive oxygen species production. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Induction of Adipocyte Differentiation by Polybrominated Diphenyl Ethers (PBDEs) in 3T3-L1 Cells

PubMed Central

Tung, Emily W. Y.; Boudreau, Adèle; Wade, Michael G.; Atlas, Ella

2014-01-01

Polybrominated diphenyl ethers (PBDEs) are a class of brominated flame retardants that were extensively used in commercial products. PBDEs are ubiquitous environmental contaminants that are both lipophilic and bioaccumulative. Effects of PBDEs on adipogenesis were studied in the 3T3-L1 preadipocyte cell model in the presence and absence of a known adipogenic agent, dexamethasone (DEX). A PBDE mixture designed to mimic body burden of North Americans was tested, in addition to the technical mixture DE-71 and the individual congener BDE-47. The mixture, DE-71, and BDE-47 all induced adipocyte differentiation as assessed by markers for terminal differentiation [fatty acid binding protein 4 (aP2) and perilipin] and lipid accumulation. Characterization of the differentiation process in response to PBDEs indicated that adipogenesis induced by a minimally effective dose of DEX was enhanced by these PBDEs. Moreover, C/EBPα, PPARγ, and LXRα were induced late in the differentiation process. Taken together, these data indicate that adipocyte differentiation is induced by PBDEs; they act in the absence of glucocorticoid and enhance glucocorticoid-mediated adipogenesis. PMID:24722056

Bergamottin Promotes Adipocyte Differentiation and Inhibits Tumor Necrosis Factor-α-induced Inflammatory Cytokines Induction in 3T3-L1 Cells.

PubMed

Mizuno, Hideya; Hatano, Tomoko; Taketomi, Ayako; Kawabata, Mami; Nakabayashi, Toshikatsu

2017-01-01

Nowadays, a lot of food ingredients are marketed as dietary supplements for health. Because the effectiveness and mechanisms of these compounds have not been fully characterized, they might have unknown functions. Therefore, we investigated the effect of several food ingredients (Bergamottin, Chrysin, L-Citrulline and β-Carotene) known as health foods on adipocyte differentiation by using 3T3-L1 preadipocytes. In this study, we found that Bergamottin, a furanocoumarin isolated from grapefruit juice, promotes adipocyte differentiation. In addition, Bergamottin increases the expression of adiponectin, an anti-inflammatory adipokine, and peroxisome proliferator activated receptor γ (PPARγ), a nuclear receptor regulating adipocyte differentiation. Furthermore, the anti-inflammatory activity of Bergamottin was demonstrated by its inhibition of the activation of nuclear factor-κB (NF-κB), an inflammatory transcription factor. Stimulation of mature 3T3-L1 adipocytes by tumor necrosis factor-α (TNF-α) decreased the expression of the endogeneous NF-κB inhibitor, IκBα. Treatment with Bergamottin further decreased the TNF-α-induced change in IκBα expression, suggesting that Bergamottin mediated the inhibition of NF-κB activation. In addition, Bergamottin decreased the TNF-α-induced increase in the mRNA levels of pro-inflammatory adipokines, monocyte chemoattractant protein-1 and interleukin-6. Taken together, our results show that Bergamottin treatment could inhibit inflammatory activity through promoting adipocyte differentiation, which in turn suggests that Bergamottin has the potential to minimize the risk factors of metabolic syndrome.

Adipocytes promote cholangiocarcinoma metastasis through fatty acid binding protein 4.

PubMed

Nie, Jihua; Zhang, Jingying; Wang, Lili; Lu, Lunjie; Yuan, Qian; An, Fangmei; Zhang, Shuyu; Jiao, Yang

2017-12-13

The early occurrence regional nodal and distant metastases cholangiocarcinoma (CCA) is one of the major reasons for its poor prognosis. However, the related mechanisms are largely elusive. Recently, increasing evidences indicate that adipocytes might be involved in the proliferation, homing, migration and invasion of several malignancies. In the present study, we attempt to determine the effects and possible mechanisms of adipocytes on regulating progression of CCA. Adipocyte-CCA cell co-culture system and CCA metastasis mice model were used to determine the effects of adipocytes on CCA metastasis. We identified the biological functions and possible mechanisms of adipocyte-derived fatty acid binding protein 4 (FABP4) in regulating the adipocyte-induced CCA metastasis and epithelial-mesenchymal transition (EMT) phenotypes, both in vitro and in vivo. Adipocyte-CCA cell co-culture promotes the in vitro and in vivo tumor metastasis, leading to increased adipocyte-derived fatty acid absorbance and intracellular lipids of CCA cells, which indicates adipocytes might function as the energy source for CCA progression by providing free fatty acids. Further, highly expressed FABP4 protein was identified in adipose tissues and fully differentiated adipocytes, and upregulated FABP4 was also detected by qRT-PCR assay in CCA cells co-cultivated with adipose extracts as compared to parental CCA cells. The specific FABP4 inhibitor BMS309403 significantly impaired adipocyte-induced CCA metastasis and EMT phenotypes both in vitro and in vivo. Together, the results demonstrate that the adipocyte-CCA interaction and the energy extraction of CCA cells from adipocytes are crucial for the invasion, migration and EMT of CCA cells. FABP4 from adipocytes mediates these adipocyte-induced variations in CCA cells, which could serve as a potential target for the treatment of CCA.

New Insights into Cytosolic Glucose Levels during Differentiation of 3T3-L1 Fibroblasts into Adipocytes*

PubMed Central

Kovacic, Petra Brina; Chowdhury, Helena H.; Velebit, Jelena; Kreft, Marko; Jensen, Jørgen; Zorec, Robert

2011-01-01

Cytosolic glucose concentration reflects the balance between glucose entry across the plasma membrane and cytosolic glucose utilization. In adipocytes, glucose utilization is considered very rapid, meaning that every glucose molecule entering the cytoplasm is quickly phosphorylated. Thus, the cytosolic free glucose concentration is considered to be negligible; however, it was never measured directly. In the present study, we monitored cytosolic glucose dynamics in 3T3-L1 fibroblasts and adipocytes by expressing a fluorescence resonance energy transfer (FRET)-based glucose nanosensor: fluorescent indicator protein FLIPglu-600μ. Specifically, we monitored cytosolic glucose responses by varying transmembrane glucose concentration gradient. The changes in cytosolic glucose concentration were detected in only 56% of 3T3-L1 fibroblasts and in 14% of 3T3-L1 adipocytes. In adipocytes, the resting cytosolic glucose concentration was reduced in comparison with the one recorded in fibroblasts. Membrane permeabilization increased cytosolic glucose concentration in adipocytes, and glycolytic inhibitor iodoacetate failed to increase cytosolic glucose concentration, indicating low adipocyte permeability for glucose at rest. We also examined the effects of insulin and adrenaline. Insulin significantly increased cytosolic glucose concentration in adipocytes by a factor of 3.6; however, we recorded no effect on delta ratio (ΔR) in fibroblasts. Adrenaline increased cytosolic glucose concentration in fibroblasts but not in adipocytes. However, in adipocytes in insulin-stimulated conditions, glucose clearance was significantly faster following adrenaline addition in comparison with controls (p < 0.001). Together, these results demonstrate that during differentiation, adipocytes develop more efficient mechanisms for maintaining low cytosolic glucose concentration, predominantly with reduced membrane permeability for glucose. PMID:21349852

Interaction between human mature adipocytes and lymphocytes induces T-cell proliferation.

PubMed

Poloni, Antonella; Maurizi, Giulia; Ciarlantini, Marco; Medici, Martina; Mattiucci, Domenico; Mancini, Stefania; Maurizi, Angela; Falconi, Massimo; Olivieri, Attilio; Leoni, Pietro

2015-09-01

Adipose tissue is a critical organ that plays a major role in energy balance regulation and the immune response through intricate signals. We report on the inter-relation between mature adipocytes and lymphocytes in terms of adipocyte-derived T-cell chemo-attractants and adipocyte metabolic effects on lymphocytes. During the culture time, mature adipocytes changed their structural and functional properties into de-differentiated cells. Isolated mature adipocytes expressed significantly higher levels of CIITA, major histocompatibility complex II (human leukocyte antigen [HLA]-DR) and costimulatory signal molecule CD80 compared with adipocytes after the de-differentiation process. Moreover, human leukocyte antigen-G, which may prevent the immune responses of mesenchymal stromal cells, was expressed at lower level in mature adipocytes compared with de-differentiated adipocytes. In line with these molecular data, functional results showed different immunoregulatory properties between adipocytes before and after the de-differentiation process. Mature adipocytes stimulated the proliferation of total lymphocytes and immunoselected cell populations CD3+, CD4+ and CD8+ in a direct contact-dependent way that involved the major histocompatibility complex I and II pathways. Moreover, adipocytes secreted potential chemo-attractant factors, but data showed that adipocyte-derived culture medium was not sufficient to activate lymphocyte proliferation, suggesting that a direct contact between adipocytes and immune cells was needed. However, specific mature adipocyte cytokines enhanced lymphocyte proliferation in a mixed lymphocyte reaction. In conclusion, cross-talk occurs between adipocytes and lymphocytes within adipose tissue involving T-cell chemo-attraction by mature adipocytes. Our findings, together with current observations in the field, provide a rationale to identify adipocyte-lymphocyte cross-talk that instigates adipose inflammation. Copyright © 2015 International

SREBP-1c/MicroRNA 33b Genomic Loci Control Adipocyte Differentiation

PubMed Central

Price, Nathan L.; Holtrup, Brandon; Kwei, Stephanie L.; Wabitsch, Martin; Rodeheffer, Matthew; Bianchini, Laurence; Suárez, Yajaira

2016-01-01

White adipose tissue (WAT) is essential for maintaining metabolic function, especially during obesity. The intronic microRNAs miR-33a and miR-33b, located within the genes encoding sterol regulatory element-binding protein 2 (SREBP-2) and SREBP-1, respectively, are transcribed in concert with their host genes and function alongside them to regulate cholesterol, fatty acid, and glucose metabolism. SREBP-1 is highly expressed in mature WAT and plays a critical role in promoting in vitro adipocyte differentiation. It is unknown whether miR-33b is induced during or involved in adipogenesis. This is in part due to loss of miR-33b in rodents, precluding in vivo assessment of the impact of miR-33b using standard mouse models. This work demonstrates that miR-33b is highly induced upon differentiation of human preadipocytes, along with SREBP-1. We further report that miR-33b is an important regulator of adipogenesis, as inhibition of miR-33b enhanced lipid droplet accumulation. Conversely, overexpression of miR-33b impaired preadipocyte proliferation and reduced lipid droplet formation and the induction of peroxisome proliferator-activated receptor γ (PPARγ) target genes during differentiation. These effects may be mediated by targeting of HMGA2, cyclin-dependent kinase 6 (CDK6), and other predicted miR-33b targets. Together, these findings demonstrate a novel role of miR-33b in the regulation of adipocyte differentiation, with important implications for the development of obesity and metabolic disease. PMID:26830228

Effects of water extract of Cajanus cajan leaves on the osteogenic and adipogenic differentiation of mouse primary bone marrow stromal cells and the adipocytic trans-differentiation of mouse primary osteoblasts.

PubMed

Zhang, Jinchao; Liu, Cuilian; Sun, Jing; Liu, Dandan; Wang, Peng

2010-01-01

The effects of water extract of Cajanus cajan (Linn.) Millsp. (Leguminosae) leaves (WECML) on the osteogenic and adipogenic differentiation of mouse primary bone marrow stromal cells (BMSCs) and the adipocytic trans-differentiation of mouse primary osteoblasts (OBs) were studied. The results indicated that WECML promoted the proliferation of BMSCs and OBs at most concentrations. WECML promoted the osteogenic differentiation and formation of mineralized matrix nodules of BMSCs at concentrations of 0.1, 1, and 10 microg/mL, but inhibited the osteogenic differentiation and formation of mineralized matrix nodules of BMSCs at concentration of 0.01 microg/mL. WECML inhibited the adipogenic differentiation of BMSCs and adipocytic trans-differentiation of OBs at concentrations of 0.001, 0.1, 1, 10, and 100 microg/mL, but had no effects at concentration of 0.01 microg/mL. The results suggest that WECML has protective effects on bone and these protective effects may be mediated by decreasing adipocytic cell formation from BMSCs, which may promote the proliferation, differentiation, and mineralization function of OBs. The defined active ingredients in the WECML and the active mechanism need to be further studied.

The adaptor protein alpha-syntrophin regulates adipocyte lipid droplet growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisinger, Kristina; Rein-Fischboeck, Lisa; Pohl, Rebekka

The scaffold protein alpha-syntrophin (SNTA) regulates lipolysis indicating a role in lipid homeostasis. Adipocytes are the main lipid storage cells in the body, and here, the function of SNTA has been analyzed in 3T3-L1 cells. SNTA is expressed in preadipocytes and is induced early during adipogenesis. Knock-down of SNTA in preadipocytes increases their proliferation. Proteins which are induced during adipogenesis like adiponectin and caveolin-1, and the inflammatory cytokine IL-6 are at normal levels in the mature cells differentiated from preadipocytes with low SNTA. This suggests that SNTA does neither affect differentiation nor inflammation. Expression of proteins with a role inmore » cholesterol and triglyceride homeostasis is unchanged. Consequently, basal and epinephrine induced lipolysis as well as insulin stimulated phosphorylation of Akt and ERK1/2 are normal. Importantly, adipocytes with low SNTA form smaller lipid droplets and store less triglycerides. Stearoyl-CoA reductase and MnSOD are reduced upon SNTA knock-down but do not contribute to lower lipid levels. Oleate uptake is even increased in cells with SNTA knock-down. In summary, current data show that SNTA is involved in the expansion of lipid droplets independent of adipogenesis. Enhanced preadipocyte proliferation and capacity to store surplus fatty acids may protect adipocytes with low SNTA from lipotoxicity in obesity. - Highlights: • Alpha-syntrophin (SNTA) is expressed in 3T3-L1adipocytes. • SNTA knock-down in preadipocytes has no effect on adipogenesis. • Mature 3T3-L1 differentiated from cells with low SNTA form small lipid droplets. • SCD1 and MnSOD are reduced in adipocytes with low SNTA. • SCD1 knock-down does not alter triglyceride levels.« less

Differential modulation of ROS signals and other mitochondrial parameters by the antioxidants MitoQ, resveratrol and curcumin in human adipocytes.

PubMed

Hirzel, Estelle; Lindinger, Peter W; Maseneni, Swarna; Giese, Maria; Rhein, Véronique Virginie; Eckert, Anne; Hoch, Matthias; Krähenbühl, Stephan; Eberle, Alex N

2013-10-01

Mitochondrial reactive oxygen species (ROS) have been demonstrated to play an important role as signaling and regulating molecules in human adipocytes. In order to evaluate the differential modulating roles of antioxidants, we treated human adipocytes differentiated from human bone marrow-derived mesenchymal stem cells with MitoQ, resveratrol and curcumin. The effects on ROS, viability, mitochondrial respiration and intracellular ATP levels were examined. MitoQ lowered both oxidizing and reducing ROS. Resveratrol decreased reducing and curcumin oxidizing radicals only. All three substances slightly decreased state III respiration immediately after addition. After 24 h of treatment, MitoQ inhibited both basal and uncoupled oxygen consumption, whereas curcumin and resveratrol had no effect. Intracellular ATP levels were not altered. This demonstrates that MitoQ, resveratrol and curcumin exert potent modulating effects on ROS signaling in human adipocyte with marginal effects on metabolic parameters.

PIM-1 kinase expression in adipocytic neoplasms: diagnostic and biological implications

PubMed Central

Nga, Min En; Swe, Nu Nu Ma; Chen, Kang Ting; Shen, Liang; Lilly, Michael B; Chan, Siew Pang; Salto-Tellez, Manuel; Das, Kakoli

2010-01-01

The differential diagnosis of soft tissue tumours poses a considerable challenge for pathologists, especially adipocytic tumours, as these may show considerable overlap in clinical presentation and morphological features with many other mesenchymal neoplasms. Hence, a specific and reliable marker that identifies adipocytic differentiation is much sought. We investigated the immunohistochemical expression of PIM-1 kinase in 35 samples of soft tissue tumours using tissue microarray technology and 49 full sections of adipocytic (n = 26) and non-adipocytic tumours (n = 23). Benign and malignant adipocytic tumours showed strong expression of PIM-1 while the non-adipocytic tumours were either negative or showed only weak staining for the protein. In myxoid liposarcomas, PIM-1 showed a distinct, unique vacuolar staining pattern, clearly outlining fine cytoplasmic lipid vacuoles. By contrast, non-adipocytic myxoid tumours (myxoma, chordoma and myxoid chondrosarcoma) did not show this vacuolar pattern of PIM-1 staining, although vacuolated cells were present on H&E. This differential expression was confirmed at a gene expression level in selected cases. Our results indicate that the expression of PIM-1 in adipose tissue may be a useful marker of adipocytic differentiation, in particular if the staining is both of high intensity and present in a unique, vacuolar pattern. PMID:19878356

Averrhoa carambola L. peel extract suppresses adipocyte differentiation in 3T3-L1 cells.

PubMed

Rashid, Asyifah Mohamed; Lu, Kaihui; Yip, Yew Mun; Zhang, Dawei

2016-02-01

Obesity is associated with an increased risk of many chronic diseases. Recently, a growing body of evidence has shown that phytochemicals may inhibit adipogenesis and obesity. In this study, we report for the first time, the ability of Averrhoa carambola L. peel extract commonly known as star fruit (SFP) to effectively suppress adipocyte differentiation in 3T3-L1 preadipocytes and therefore, address it as a potential candidate to treat obesity and its related diseases. (-)-Epicatechin was identified as a bioactive compound likely responsible for this suppression. As the genetic expression studies revealed that the adipogenic activity of SFP extract was due to the simultaneous downregulation of the C/EBPα and PPARγ as well as the upregulation of PPARα receptor genes, a detailed computational docking study was also elucidated to reveal the likely binding mode of (-)-epicatechin to the receptor of interest, accounting for the likely mechanism that results in the overall suppression of adipocyte differentiation.

Persimmon tannin represses 3T3-L1 preadipocyte differentiation via up-regulating expression of miR-27 and down-regulating expression of peroxisome proliferator-activated receptor-γ in the early phase of adipogenesis.

PubMed

Zou, Bo; Ge, Zhenzhen; Zhu, Wei; Xu, Ze; Li, Chunmei

2015-12-01

Currently, obesity has become a worldwide health problem. Adipocyte differentiation is closely associated with the onset of obesity. Our previous studies suggested that persimmon tannin might be a potent anti-adipogenic dietary bioactive compound. However, the mechanism of persimmon tannin on adipocyte differentiation is still unknown. The purpose of this study was to investigate the effect of persimmon tannin on adipogenic differentiation in 3T3-L1 preadipocytes and the underlying mechanisms. Adipogenic differentiation was induced by cocktail in the presence or absence of persimmon tannin. Intracellular lipid accumulation was determined by Oil red O staining and enzymatic colorimetric methods. Gene expression and protein levels were measured by real time RT-PCR and Western blot. Persimmon tannin inhibited intracellular lipid accumulation markedly, and the inhibitory effect was largely limited to the early stage of adipocyte differentiation. Persimmon tannin suppressed the expression of C/EBPα and peroxisome proliferator-activated receptor-γ (PPARγ), significantly. Furthermore, genes related to lipogenesis, such as sterol regulatory element-binding protein 1, were down-regulated by persimmon tannin. In addition, adipocyte fatty acid binding protein (aP2), which is a target gene of PPARγ, was suppressed by persimmon tannin notably. Correspondingly, the expression of miR-27a and miR-27b were up-regulated by persimmon tannin from Day 2 to Day 8 significantly. Persimmon tannin inhibited adipocyte differentiation through regulation of PPARγ, C/EBPα and miR-27 in early stage of adipogenesis.

Differentiation of human pluripotent stem cells into highly functional classical brown adipocytes.

PubMed

Nishio, Miwako; Saeki, Kumiko

2014-01-01

We describe a detailed method for directed differentiation of human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced pluripotent stem cells (hiPSCs), into functional classical brown adipocytes (BAs) under serum-free and feeder-free conditions. It is a two-tiered culture system, based on very simple techniques, a floating culture and a subsequent adherent culture. It does not require gene transfer. The entire process can be carried out in about 10 days. The key point is the usage of our special hematopoietic cytokine cocktail. Almost all the differentiated cells express uncoupling protein 1, a BA-selective marker, as determined by immunostaining. The differentiated cells show characteristics of classical BA as assessed by morphology and gene/protein expression. Moreover, the expression of myoblast marker genes is transiently induced during the floating culture step. hESC/hiPSC-derived BAs show significantly higher oxygen consumption rates (OCRs) than white adipocytes generated from human mesenchymal stem cell. They also show responsiveness to adrenergic stimuli, with about twofold upregulation in OCR by β-adrenergic receptor (β-AR) agonist treatments. hESC/hiPSC-derived BAs exert in vivo calorigenic activities in response to β-AR agonist treatments as assessed by thermography. Finally, lipid and glucose metabolisms are significantly improved in hESC/hiPSC-derived BA-transplanted mice. Our system provides a highly feasible way to produce functional classical BA bearing metabolism-improving capacities from hESC/hiPSC under a feeder-free and serum-free condition without gene transfer. © 2014 Elsevier Inc. All rights reserved.

The endocrine disruptor diethylstilbestrol induces adipocyte differentiation and promotes obesity in mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hao, Chan-Juan; Cheng, Xue-Jia; Xia, Hong-Fei, E-mail: hongfeixia@yahoo.com.cn

Epidemiology studies indicate that exposure to endocrine disruptors during developmental “window” contributes to adipogenesis and the development of obesity. Implication of endocrine disruptor such as diethylstilbestrol (DES) on adipose tissue development has been poorly investigated. Here we evaluated the effects of DES on adipocyte differentiation in vitro and in vivo, and explored potential mechanism involved in its action. DES induced 3T3-L1 preadipocyte differentiation in a dose-dependent manner, and activated the expression of estrogen receptor (ER) and peroxisome proliferator-acivated receptor (PPAR) γ as well as its target genes required for adipogenesis in vitro. ER mediated the enhancement of DES-induced PPARγ activity.more » Moreover, DES perturbed key regulators of adipogenesis and lipogenic pathway in vivo. In utero exposure to low dose of DES significantly increased body weight, liver weight and fat mass in female offspring at postnatal day (PND) 60. In addition, serum triglyceride and glucose levels were also significantly elevated. These results suggest that perinatal exposure to DES may be expected to increase the incidence of obesity in a sex-dependent manner and can act as a potential chemical stressor for obesity and obesity-related disorders. -- Highlights: ► DES induced adipocyte differentiation in a dose-dependent manner in 3T3-L1 cells. ► DES activated adipogenic critical regulators and markers in vitro and in vivo. ► Perinatal exposure to DES led to the obese phenotype in female offspring. ► DES might be a potential chemical stressor for obesity and obesity-related disorders.« less

GPR120 in adipocytes has differential roles in the production of pro-inflammatory adipocytokines

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hasan, Arif Ul, E-mail: ahasan@med.kagawa-u.ac.jp; Department of Pharmacology, Faculty of Medicine, Kagawa University, 1750-1, Ikenobe, Miki-cho, Kita-gun, Kagawa 761-0793; Ohmori, Koji

GPR120 differentially regulates the pro-inflammatory adipocytokines. • Agonizing GPR120 in adipocytes attenuates NF-κB mediated IL-6 and CCL2 production. • Agonizing GPR120 concomitantly triggers a PKC mediated pro-inflammatory pathway. • However, the resulted effect in adipocytes remains anti-inflammatory. • Agonizing GPR120 in adipocytes reduces macrophage migration in a paracrine manner.« less

Differentiation of Rat bone marrow Mesenchymal stem cells into Adipocytes and Cardiomyocytes after treatment with platelet lysate.

PubMed

Homayouni Moghadam, Farshad; Tayebi, Tahereh; Barzegar, Kazem

2016-01-01

Mesenchymal stem cells (MSCs) are multipotential cells and their therapeutic potency is under intense investigation. Studying the effect of different induction factors on MSCs could increase our knowledge about the differentiation potency of these cells. One of the most important sources of these factors in mammalian body is platelet. Platelet lysate (PL) contains many growth factors and therefore, it can be used as a differentiation inducer. In the present study, the effect of PL on differentiation of rat bone marrow MSCs into cardiomyocytes was studied. To study the differentiation-inducing effect of PL, MSCs were treated with 2.5, 5 and 10% PL. Early results of this study showed that PL in high concentrations (10%) induces adipogenic differentiation of MSCs. Therefore, to evaluate differentiation to cardiomyocytes, MSCs were cultured in media containing lower levels of PL (2.5% and 5%) and then cardiomyogenic differentiation was induced by treatment with 5-azacytidine. Differentiation of MSCs was evaluated using direct observation of beating cells, immunostaining and real-time PCR techniques. The results of qPCR showed that treatment with PL alone increased the expression of cardiac alpha actinin (CAA) being predictable by earlier observation of beating cells in PL-treated groups. The results of staining assays against cardiac alpha actinin also showed that there were stained cells in PL-treated groups. The results of the present study showed that PL is a powerful induction factor for differentiation of MSCs into different cell lines such as cardiomyocytes and adipocytes.

Platyphylloside Isolated From Betula platyphylla Inhibit Adipocyte Differentiation and Induce Lipolysis Via Regulating Adipokines Including PPARγ in 3T3-L1 Cells

PubMed Central

Lee, Mina; Sung, Sang Hyun

2016-01-01

Background: Obesity causes or aggravates many health problems, both independently and in association with several pathological disorders, including Type II diabetes, hypertension, atherosclerosis, and cancer. Therefore, we screened small compounds isolated from natural products for the development of anti-obesity drugs. Objective: The purpose of this study was to investigate the anti-adipogenic activities of platyphylloside, diarylheptanoid isolated from Betula platyphylla, which was selected based on the screening using 3T3-L1 cells. Materials and Methods: To evaluate the inhibition of adipocyte differentiation and lipolysis, lipid contents of BPP on were measured using Oil Red O staining in 3T3-L1 cells. The mRNA and protein expression levels of various adipokines were measured by Quantitative real-time PCR and Western blotting analysis, respectively. Results: Platyphylloside showed significant inhibitory activity on adipocyte differentiation in 3T3-L1 cells and suppressed adipocyte differentiation even in the presence of troglitazone, a PPARγ agonist. Platyphylloside might suppress adipocyte differentiation through PPARγ, C/EBPα, and SREBP1-induced adipogenesis, which is synergistically associated with downstream adipocyte-specific gene promoters such as aP2, FAS, SCD-1, LPL, and Adiponectin. In addition, platyphylloside affected lipolysis by down-regulating perilipin and HSL and up-regulating TNFα. Conclusion: Taken together, the results reveal that platyphylloside has anti-adipogenic activity and highlight its potential in the prevention and treatment of obesity. SUMMARY The extract of B. platyphylla bark and its isolate, BPP, had anti-adipogenic activity in 3T3-L1 cells via suppression of adipocyte differentiation from preadipocytes.Treatment with BPP significantly down-regulated the expression of PPARγ, C/EBP, C/EBPβ, C/EBPδ, SREBP1c, SCD-1, FAS, aP2 and LPL.BPP induced a lipolytic response in mature adipocytes via up-regulation krof TNFá and down

α-Naphthoflavone Increases Lipid Accumulation in Mature Adipocytes and Enhances Adipocyte-Stimulated Endothelial Tube Formation.

PubMed

Wang, Mei-Lin; Lin, Shyh-Hsiang; Hou, Yuan-Yu; Chen, Yue-Hwa

2015-04-30

The aryl hydrocarbon receptor (AhR) is a ligand-activated factor that regulates biological effects associated with obesity. The AhR agonists, such as environmental contaminants 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and β-naphthoflavone (BNF), inhibit preadipocyte differentiation and interfere with the functions of adipose tissue, whereas the antagonist may have opposite or protective effects in obesity. This study investigated the effects of α-naphthoflavone (α-NF), an AhR antagonist, on adipogenesis- and angiogenesis-associated factors in mature adipocytes and on cross-talk of mature adipocytes with endothelial cells (ECs). Besides, the roles of the AhR on lipid accumulation and on secretion of vascular endothelial growth factor were also determined by introducing siRNA of AhR. Differentiated 3T3-L1 cells were treated with α-naphthoflavone (α-NF) (1-5 μM) for 16 h. Lipid accumulation and the expressions of AhR-associated factors in the cells were determined. The interaction between adipocytes and ECs was investigated by cultivating ECs with conditioned medium (CM) from α-NF-treated mature adipocytes, followed by the determination of endothelial tube formation. The results showed that α-NF significantly increased triglyceride (TG) accumulation in mature adipocytes, which was associated with increased expression of hormone-sensitive lipase (HSL), estrogen receptor (ER), as well as decreased expression of AhR, AhR nuclear translocator (ARNT), cytochrome P4501B1 (CYP1B1), and nuclear factor erythroid-2-related factor (NRF-2) proteins. In addition, CM stimulated formation of tube-like structures in ECs, and α-NF further enhanced such stimulation in association with modulated the secretions of various angiogenic mediators by mature adipocytes. Similarly, increased TG accumulation and vascular endothelial growth factor (VEGF) secretion were observed in AhR-knockout cells. In conclusion, α-NF increased TG accumulation in mature adipocytes and enhanced

Endocrine modulators of mouse subcutaneous adipose tissue beige adipocyte markers

USDA-ARS?s Scientific Manuscript database

The stromal vascular fraction (SVF) of subcutaneous adipose tissue contains precursors that can give rise to beige adipocytes. Beige adipocytes are characterized by the expression of specific markers, but it is not clear which markers best evaluate beige adipocyte differentiation. Both regulators of...

Effect of black soybean koji extract on glucose utilization and adipocyte differentiation in 3T3-L1 cells.

PubMed

Huang, Chi-Chang; Huang, Wen-Ching; Hou, Chien-Wen; Chi, Yu-Wei; Huang, Hui-Yu

2014-05-09

Adipocyte differentiation and the extent of subsequent fat accumulation are closely related to the occurrence and progression of diseases such as insulin resistance and obesity. Black soybean koji (BSK) is produced by the fermentation of black soybean with Aspergilllus awamori. Previous study indicated that BSK extract has antioxidative and multifunctional bioactivities, however, the role of BSK in the regulation of energy metabolism is still unclear. We aimed to investigate the effect of glucose utilization on insulin-resistant 3T3-L1 preadipocytes and adipogenesis-related protein expression in differentiated adipocytes with BSK treatment. Cytoxicity assay revealed that BSK did not adversely affect cell viability at levels up to 200 µg/mL. The potential for glucose utilization was increased by increased glucose transporter 1 (GLUT1), GLUT4 and protein kinase B (AKT) protein expression in insulin-resistant 3T3-L1 cells in response to BSK treatment. Simultaneously, BSK inhibited lipid droplet accumulation in differentiated 3T3-L1 cells. The inhibitory effect of adipogenesis was associated with downregulated peroxisome proliferator-activated receptor g (PPARγ) level and upregulated Acrp30 protein expression. Our results suggest that BSK extract could improve glucose uptake by modulating GLUT1 and GLUT4 expression in a 3T3-L1 insulin-resistance cell model. In addition, BSK suppressed differentiation and lipid accumulation in mature 3T3-L1 adipocytes, which may suggest its potential for food supplementation to prevent obesity and related metabolic abnormalities.

Effects of quercetin, a natural phenolic compound, in the differentiation of human mesenchymal stem cells (MSC) into adipocytes and osteoblasts.

PubMed

Casado-Díaz, Antonio; Anter, Jaouad; Dorado, Gabriel; Quesada-Gómez, José Manuel

2016-06-01

Natural phenols may have beneficial properties against oxidative stress, which is associated with aging and major chronic aging-related diseases, such as loss of bone mineral mass (osteoporosis) and diabetes. The main aim of this study was to analyze the effect of quercetin, a major nutraceutical compound present in the "Mediterranean diet", on mesenchymal stem-cell (MSC) differentiation. Such cells were induced to differentiate into osteoblasts or adipocytes in the presence of two quercetin concentrations (0.1 and 10μM). Several physiological parameters and the expression of osteoblastogenesis and adipogenesis marker genes were monitored. Quercetin (10μM) inhibited cell proliferation, alkaline phosphatase (ALPL) activity and mineralization, down-regulating the expression of ALPL, collagen type I alpha 1 (COL1A1) and osteocalcin [bone gamma-carboxyglutamate protein (BGLAP)] osteoblastogenesis-related genes in MSC differentiating into osteoblasts. Moreover, in these cultures, CCAAT/enhancer-binding protein alpha (CEBPA) and peroxisome proliferator-activated receptor gamma 2 (PPARG2) adipogenic genes were induced, and cells differentiated into adipocytes were observed. Quercetin did not affect proliferation, but increased adipogenesis, mainly at 10-μM concentration in MSC induced to differentiate to adipocytes. β- and γ-catenin (plakoglobin) nuclear levels were reduced and increased, respectively, in quercetin-treated cultures. This suggests that the effect of high concentration of quercetin on MSC osteoblastic and adipogenic differentiation is mediated via Wnt/β-catenin inhibition. In conclusion, quercetin supplementation inhibited osteoblastic differentiation and promoted adipogenesis at the highest tested concentration. Such possible adverse effects of high quercetin concentrations should be taken into account in nutraceutical or pharmaceutical strategies using such flavonol. Copyright © 2016 Elsevier Inc. All rights reserved.

Differentiation of Rat bone marrow Mesenchymal stem cells into Adipocytes and Cardiomyocytes after treatment with platelet lysate

PubMed Central

Homayouni Moghadam, Farshad; Tayebi, Tahereh; Barzegar, Kazem

2016-01-01

Background: Mesenchymal stem cells (MSCs) are multipotential cells and their therapeutic potency is under intense investigation. Studying the effect of different induction factors on MSCs could increase our knowledge about the differentiation potency of these cells. One of the most important sources of these factors in mammalian body is platelet. Platelet lysate (PL) contains many growth factors and therefore, it can be used as a differentiation inducer. In the present study, the effect of PL on differentiation of rat bone marrow MSCs into cardiomyocytes was studied. Materials and Methods: To study the differentiation-inducing effect of PL, MSCs were treated with 2.5, 5 and 10% PL. Early results of this study showed that PL in high concentrations (10%) induces adipogenic differentiation of MSCs. Therefore, to evaluate differentiation to cardiomyocytes, MSCs were cultured in media containing lower levels of PL (2.5% and 5%) and then cardiomyogenic differentiation was induced by treatment with 5-azacytidine. Differentiation of MSCs was evaluated using direct observation of beating cells, immunostaining and real-time PCR techniques. Results: The results of qPCR showed that treatment with PL alone increased the expression of cardiac alpha actinin (CAA) being predictable by earlier observation of beating cells in PL-treated groups. The results of staining assays against cardiac alpha actinin also showed that there were stained cells in PL-treated groups. Conclusion: The results of the present study showed that PL is a powerful induction factor for differentiation of MSCs into different cell lines such as cardiomyocytes and adipocytes. PMID:27047647

Nitric oxide balances osteoblast and adipocyte lineage differentiation via the JNK/MAPK signaling pathway in periodontal ligament stem cells.

PubMed

Yang, Shan; Guo, Lijia; Su, Yingying; Wen, Jing; Du, Juan; Li, Xiaoyan; Liu, Yitong; Feng, Jie; Xie, Yongmei; Bai, Yuxing; Wang, Hao; Liu, Yi

2018-05-02

Critical tissues that undergo regeneration in periodontal tissue are of mesenchymal origin; thus, investigating the regulatory mechanisms underlying the fate of periodontal ligament stem cells could be beneficial for application in periodontal tissue regeneration. Nitric oxide (NO) regulates many biological processes in developing embryos and adult stem cells. The present study was designed to investigate the effects of NO on the function of human periodontal ligament stem cells (PDLSCs) as well as to elucidate the underlying molecular mechanisms. Immunofluorescent staining and flow cytometry were used for stem cell identification. Western blot, reverse transcription polymerase chain reaction (RT-PCR), immunofluorescent staining, and flow cytometry were used to examine the expression of NO-synthesizing enzymes. The proliferative capacity of PDLSCs was determined by EdU assays. The osteogenic potential of PDLSCs was tested using alkaline phosphatase (ALP) staining, Alizarin Red staining, and calcium concentration detection. Oil Red O staining was used to analyze the adipogenic ability. Western blot, RT-PCR, and staining were used to examine the signaling pathway. Human PDLSCs expressed both inducible NO synthase (iNOS) and endothelial NO synthase (eNOS) and produced NO. Blocking the generation of NO with the NOS inhibitor L-N G -monomethyl arginine (L-NMMA) had no influence on PDLSC proliferation and apoptosis but significantly attenuated the osteogenic differentiation capacity and stimulated the adipogenic differentiation capacity of PDLSCs. Increasing the physiological level of NO with NO donor sodium nitroprusside (SNP) significantly promoted the osteogenic differentiation capacity but reduced the adipogenic differentiation capacity of PDLSCs. NO balances the osteoblast and adipocyte lineage differentiation in periodontal ligament stem cells via the c-Jun N-terminal kinase (JNK)/mitogen-activated protein kinase (MAPK) signaling pathway. NO is essential for

Effects of Leucine Supplementation and Serum Withdrawal on Branched-Chain Amino Acid Pathway Gene and Protein Expression in Mouse Adipocytes

PubMed Central

Vivar, Juan C.; Knight, Megan S.; Pointer, Mildred A.; Gwathmey, Judith K.; Ghosh, Sujoy

2014-01-01

The essential branched-chain amino acids (BCAA), leucine, valine and isoleucine, are traditionally associated with skeletal muscle growth and maintenance, energy production, and generation of neurotransmitter and gluconeogenic precursors. Recent evidence from human and animal model studies has established an additional link between BCAA levels and obesity. However, details of the mechanism of regulation of BCAA metabolism during adipogenesis are largely unknown. We interrogated whether the expression of genes and proteins involved in BCAA metabolism are sensitive to the adipocyte differentiation process, and responsive to nutrient stress from starvation or BCAA excess. Murine 3T3-L1 preadipocytes were differentiated to adipocytes under control conditions and under conditions of L-leucine supplementation or serum withdrawal. RNA and proteins were isolated at days 0, 4 and 10 of differentiation to represent pre-differentiation, early differentiation and late differentiation stages. Expression of 16 BCAA metabolism genes was quantified by quantitative real-time PCR. Expression of the protein levels of branched-chain amino acid transaminase 2 (Bcat2) and branched-chain alpha keto acid dehydrogenase (Bckdha) was quantified by immunoblotting. Under control conditions, all genes displayed induction of gene expression during early adipogenesis (Day 4) compared to Day 0. Leucine supplementation resulted in an induction of Bcat2 and Bckdha genes during early and late differentiation. Western blot analysis demonstrated condition-specific concordance between gene and protein expression. Serum withdrawal resulted in undetectable Bcat2 and Bckdha protein levels at all timepoints. These results demonstrate that the expression of genes related to BCAA metabolism are regulated during adipocyte differentiation and influenced by nutrient levels. These results provide additional insights on how BCAA metabolism is associated with adipose tissue function and extends our understanding of

SIRT1 Limits Adipocyte Hyperplasia through c-Myc Inhibition*

PubMed Central

Abdesselem, Houari; Madani, Aisha; Hani, Ahmad; Al-Noubi, Muna; Goswami, Neha; Ben Hamidane, Hisham; Billing, Anja M.; Pasquier, Jennifer; Bonkowski, Michael S.; Halabi, Najeeb; Dalloul, Rajaa; Sheriff, Mohamed Z.; Mesaeli, Nasrin; ElRayess, Mohamed; Sinclair, David A.; Graumann, Johannes; Mazloum, Nayef A.

2016-01-01

The expansion of fat mass in the obese state is due to increased adipocyte hypertrophy and hyperplasia. The molecular mechanism that drives adipocyte hyperplasia remains unknown. The NAD+-dependent protein deacetylase sirtuin 1 (SIRT1), a key regulator of mammalian metabolism, maintains proper metabolic functions in many tissues, counteracting obesity. Here we report that differentiated adipocytes are hyperplastic when SIRT1 is knocked down stably in mouse 3T3-L1 preadipocytes. This phenotype is associated with dysregulated adipocyte metabolism and enhanced inflammation. We also demonstrate that SIRT1 is a key regulator of proliferation in preadipocytes. Quantitative proteomics reveal that the c-Myc pathway is altered to drive enhanced proliferation in SIRT1-silenced 3T3-L1 cells. Moreover, c-Myc is hyperacetylated, levels of p27 are reduced, and cyclin-dependent kinase 2 (CDK2) is activated upon SIRT1 reduction. Remarkably, differentiating SIRT1-silenced preadipocytes exhibit enhanced mitotic clonal expansion accompanied by reduced levels of p27 as well as elevated levels of CCAAT/enhancer-binding protein β (C/EBPβ) and c-Myc, which is also hyperacetylated. c-Myc activation and enhanced proliferation phenotype are also found to be SIRT1-dependent in proliferating mouse embryonic fibroblasts and differentiating human SW872 preadipocytes. Reducing both SIRT1 and c-Myc expression in 3T3-L1 cells simultaneously does not induce the adipocyte hyperplasia phenotype, confirming that SIRT1 controls adipocyte hyperplasia through c-Myc regulation. A better understanding of the molecular mechanisms of adipocyte hyperplasia will open new avenues toward understanding obesity. PMID:26655722

Extending Human Hematopoietic Stem Cell Survival In Vitro with Adipocytes

PubMed Central

Glettig, Dean Liang

2013-01-01

Abstract Human hematopoietic stem cells (hHSCs) cannot be maintained in vitro for extended time periods because they rapidly differentiate or die. To extend in vitro culture time, researchers have made attempts to use human mesenchymal stem cells (hMSCs) to create feeder layers that mimic the stem cell niche. We have conducted an array of experiments including adipocytes in these feeder layers that inhibit hHSC differentiation and by that prolong stem cell survival in vitro. The amount of CD34+ cells was quantified using flow cytometry. In a first experiment, feeder layers of undifferentiated hMSCs were compared with feeder layers differentiated toward osteoblasts or adipocytes using minimal medium, showing the highest survival rate where adipocytes were included. The same conclusion was drawn in a second experiment in comparing hMSCs with adipogenic feeder cells, using a culture medium supplemented with a cocktail of hHSC growth factors. In a third experiment, it was shown that direct cell–cell contact is necessary for the supportive effect of the feeder layers. In a fourth and fifth experiment the amount of adipocytes in the feeder layers were varied, and in all experiments a higher amount of adipocytes in the feeder layers showed a less rapid decay of CD34+ cells at later time points. We therefore concluded that adipocytes assist in suppressing hHSC differentiation and aid in prolonging their survival in vitro. PMID:23741628

Connective tissue growth factor regulates adipocyte differentiation of mesenchymal stromal cells and facilitates leukemia bone marrow engraftment

PubMed Central

Battula, V. Lokesh; Chen, Ye; Cabreira, Maria da Graca; Ruvolo, Vivian; Wang, Zhiqiang; Ma, Wencai; Konoplev, Sergej; Shpall, Elizabeth; Lyons, Karen; Strunk, Dirk; Bueso-Ramos, Carlos; Davis, Richard Eric; Konopleva, Marina

2013-01-01

Mesenchymal stromal cells (MSCs) are a major component of the leukemia bone marrow (BM) microenvironment. Connective tissue growth factor (CTGF) is highly expressed in MSCs, but its role in the BM stroma is unknown. Therefore, we knocked down (KD) CTGF expression in human BM-derived MSCs by CTGF short hairpin RNA. CTGF KD MSCs exhibited fivefold lower proliferation compared with control MSCs and had markedly fewer S-phase cells. CTGF KD MSCs differentiated into adipocytes at a sixfold higher rate than controls in vitro and in vivo. To study the effect of CTGF on engraftment of leukemia cells into BM, an in vivo model of humanized extramedullary BM (EXM-BM) was developed in NOD/SCID/IL-2rgnull mice. Transplanted Nalm-6 or Molm-13 human leukemia cells engrafted at a threefold higher rate in adipocyte-rich CTGF KD MSC-derived EXM-BM than in control EXM-BM. Leptin was found to be highly expressed in CTGF KD EXM-BM and in BM samples of patients with acute myeloid and acute lymphoblastic leukemia, whereas it was not expressed in normal controls. Given the established role of the leptin receptor in leukemia cells, the data suggest an important role of CTGF in MSC differentiation into adipocytes and of leptin in homing and progression of leukemia. PMID:23741006

Effects of MicroRNA-23a on Differentiation and Gene Expression Profiles in 3T3-L1 Adipocytes

PubMed Central

Huang, Yong; Huang, Jinxiu; Qi, Renli; Wang, Qi; Wu, Yongjiang; Wang, Jing

2016-01-01

MicroRNAs (miRNAs) are small non-coding RNA molecules that regulate growth, development, and programmed death of cells. A newly-published study has shown that miRNA-23a could regulate 3T3-L1 adipocyte differentiation. Here, we identified miRNA-23a as a negative regulator of 3T3-L1 adipocyte differentiation again. Over-expression of miRNA-23a inhibited differentiation and decreased lipogenesis as well as down-regulated mRNA and protein expression of both peroxisome proliferator-activated receptor (PPAR) γ and fatty acid binding protein (FABP) 4, whereas knock down of miRNA-23a showed the opposite effects on differentiation as well as increasing the number of apoptotic cells. Additionally, digital gene expression profiling sequencing (DGE-Seq) was used to assay changes in gene expression profiles following alterations in the level of miR-23a. In total, over-expression or knock down of miRNA-23a significantly changed the expression of 313 and 425 genes, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that these genes were mainly involved in the stress response, immune system, metabolism, cell cycle, among other pathways. Additionally, the signal transducer and activator of transcription 1 (Stat1) was shown to be a target of miRNA-23a by computational and dual-luciferase reporter assays that indicated Janus Kinase (Jak)-Stat signal pathway was implicated in regulating adipogenesis mediated by miRNA-23a in adipocytes. PMID:27783036

Regulation of adipocytokine secretion and adipocyte hypertrophy by polymethoxyflavonoids, nobiletin and tangeretin.

PubMed

Miyata, Yoshiki; Tanaka, Haruyuki; Shimada, Arata; Sato, Takashi; Ito, Akira; Yamanouchi, Toshikazu; Kosano, Hiroshi

2011-03-28

The polymethoxyflavonoids nobiletin and tangeretin possess several important biological properties such as neuroprotective, antimetastatic, anticancer, and anti-inflammatory properties. The present study was undertaken to examine whether nobiletin and tangeretin could modulate adipocytokine secretion and to evaluate the effects of these flavonoids on the hypertrophy of mature adipocytes. All experiments were performed on the murine preadipocyte cell line 3T3-L1. We studied the formation of intracellular lipid droplets in adipocytes and the apoptosis-inducing activity to evaluate the effects of polymethoxyflavonoids on adipocyte differentiation and hypertrophy, respectively. The secretion of adipocytokines was measured using ELISA. We demonstrated that the combined treatment of differentiation reagents with nobiletin or tangeretin differentiated 3T3-L1 preadipocytes into adipocytes possessing less intracellular triglyceride as compared to vehicle-treated differentiated 3T3-L1 adipocytes. Both flavonoids increased the secretion of an insulin-sensitizing factor, adiponectin, but concomitantly decreased the secretion of an insulin-resistance factor, MCP-1, in 3T3-L1 adipocytes. Furthermore, nobiletin was found to decrease the secretion of resistin, which serves as an insulin-resistance factor. In mature 3T3-L1 adipocytes, nobiletin induced apoptosis; tangeretin, in contrast, did not induce apoptosis, but suppressed further triglyceride accumulation. Our results suggest that nobiletin and tangeretin are promising therapeutic candidates for the prevention and treatment of insulin resistance by modulating the adipocytokine secretion balance. We also demonstrated the different effects of nobiletin and tangeretin on mature adipocytes. Copyright © 2011 Elsevier Inc. All rights reserved.

Activation of peroxisome proliferator-activated receptor-{alpha} enhances fatty acid oxidation in human adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Joo-Young; Hashizaki, Hikari; Goto, Tsuyoshi

2011-04-22

Highlights: {yields} PPAR{alpha} activation increased mRNA expression levels of adipocyte differentiation marker genes and GPDH activity in human adipocytes. {yields} PPAR{alpha} activation also increased insulin-dependent glucose uptake in human adipocytes. {yields} PPAR{alpha} activation did not affect lipid accumulation in human adipocytes. {yields} PPAR{alpha} activation increased fatty acid oxidation through induction of fatty acid oxidation-related genes in human adipocytes. -- Abstract: Peroxisome proliferator-activated receptor-{alpha} (PPAR{alpha}) is a key regulator for maintaining whole-body energy balance. However, the physiological functions of PPAR{alpha} in adipocytes have been unclarified. We examined the functions of PPAR{alpha} using human multipotent adipose tissue-derived stem cells as a humanmore » adipocyte model. Activation of PPAR{alpha} by GW7647, a potent PPAR{alpha} agonist, increased the mRNA expression levels of adipocyte differentiation marker genes such as PPAR{gamma}, adipocyte-specific fatty acid-binding protein, and lipoprotein lipase and increased both GPDH activity and insulin-dependent glucose uptake level. The findings indicate that PPAR{alpha} activation stimulates adipocyte differentiation. However, lipid accumulation was not changed, which is usually observed when PPAR{gamma} is activated. On the other hand, PPAR{alpha} activation by GW7647 treatment induced the mRNA expression of fatty acid oxidation-related genes such as CPT-1B and AOX in a PPAR{alpha}-dependent manner. Moreover, PPAR{alpha} activation increased the production of CO{sub 2} and acid soluble metabolites, which are products of fatty acid oxidation, and increased oxygen consumption rate in human adipocytes. The data indicate that activation of PPAR{alpha} stimulates both adipocyte differentiation and fatty acid oxidation in human adipocytes, suggesting that PPAR{alpha} agonists could improve insulin resistance without lipid accumulation in adipocytes. The

Using Brillouin microspectroscopy to characterize adipocytes' response to lipid droplet accumulation

NASA Astrophysics Data System (ADS)

Troyanova-Wood, Maria; Coker, Zachary; Traverso, Andrew; Yakovlev, Vladislav V.

2017-02-01

Obesity and overweight are accompanied by an enlargement of adipocytes, which is commonly related to the increasing number or size of lipid droplets within the cells. Some studies have shown that the accumulation of lipid droplets within adipocytes results in their increased stiffness. Recently, Brillouin microspectroscopy has been introduced as a nondestructive method of imaging the elasticity of cells. Unlike other imaging modalities, it is capable of assessing the elastic properties on both tissue- and cell levels. In this study, Brillouin spectroscopy was used to measure the elasticity changes in response to accumulation of lipid droplets within adipocyte during adipogenesis. The cell line used in the study is 3T3-L1, with chemically-induced differentiation from pre-adipocytes to mature adipocytes. The Brillouin shift measurements of the cells before and after differentiation indicate that the stiffness of adipocytes increases due to accumulation of lipid droplets. The results are in agreement with previous atomic force microscopy (AFM) nanoindentation studies. Brillouin microspectroscopy is a technique suitable for measuring the changes of elasticity of adipocytes in response to lipid droplet accumulation.

Tributyltin and triphenyltin exposure promotes in vitro adipogenic differentiation but alters the adipocyte phenotype in rainbow trout.

PubMed

Lutfi, Esmail; Riera-Heredia, Natàlia; Córdoba, Marlon; Porte, Cinta; Gutiérrez, Joaquim; Capilla, Encarnación; Navarro, Isabel

2017-07-01

Numerous environmental pollutants have been identified as potential obesogenic compounds affecting endocrine signaling and lipid homeostasis. Among them, well-known organotins such as tributyltin (TBT) and triphenyltin (TPT), can be found in significant concentrations in aquatic environments. The aim of the present study was to investigate in vitro the effects of TBT and TPT on the development and lipid metabolism of rainbow trout (Onchorynchus mykiss) primary cultured adipocytes. Results showed that TBT and TPT induced lipid accumulation and slightly enhanced peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT enhancer binding protein alpha (C/EBPα) protein expression when compared to a control, both in the presence or absence of lipid mixture. However, the effects were higher when combined with lipid, and in the absence of it, the organotins did not cause complete mature adipocyte morphology. Regarding gene expression analyses, exposure to TBT and TPT caused an increase in fatty acid synthase (fasn) mRNA levels confirming the pro-adipogenic properties of these compounds. In addition, when added together with lipid, TBT and TPT significantly increased cebpa, tumor necrosis factor alpha (tnfa) and ATP-binding cassette transporter 1 (abca1) mRNA levels suggesting a synergistic effect. Overall, our data highlighted that TBT and TPT activate adipocyte differentiation in rainbow trout supporting an obesogenic role for these compounds, although by themselves they are not able to induce complete adipocyte development and maturation suggesting that these adipocytes might not be properly functional. Copyright © 2017 Elsevier B.V. All rights reserved.

Differentiation of rat brown adipocytes during late foetal development: role of insulin-like growth factor I.

PubMed Central

Teruel, T; Valverde, A M; Alvarez, A; Benito, M; Lorenzo, M

1995-01-01

Rat brown adipocytes at day 22 of foetal development showed greater size, higher mitochondria content and larger amounts of lipids, as determined by flow cytometry, than 20-day foetal cells. Simultaneously, an inhibition on the percentage of brown adipocytes into S+G2/M phases of the cell cycle was observed between days 20 and 22 of foetal development. The expression of several adipogenesis-related genes, such as fatty acid synthase, malic enzyme, glucose-6-phosphate dehydrogenase and insulin-regulated glucose transporter, increased at the end of foetal life in brown adipose tissue. In addition, the lipogenic enzyme activities and the lipogenic flux increased during late foetal development, resulting in mature brown adipocytes showing a multilocular fat droplet phenotype. Concurrently, brown adipocytes induced the expression of the uncoupling protein (UP) mRNA and UP protein, as visualized by immunofluorescence. The three isoforms of CCAAT enhancer-binding proteins (C/EBPs) were expressed at the mRNA level in brown adipose tissue at day 20. C/EBP alpha decreased and C/EBP beta and delta increased their expression between days 20 and 22 of foetal development, respectively. Brown adipose tissue constitutively expressed insulin-like growth factor I (IGF-I) and IGF-I receptor (IGF-IR) mRNAs. Moreover, IGF-IR mRNA content increased between days 20 and 22 in parallel with the occurrence of tissue differentiation. Images Figure 2 Figure 3 Figure 4 PMID:7575409

Effects of Tithonia diversifolia (Hemsl.) A. Gray Extract on Adipocyte Differentiation of Human Mesenchymal Stem Cells

PubMed Central

Di Giacomo, Claudia; Vanella, Luca; Sorrenti, Valeria; Santangelo, Rosa; Barbagallo, Ignazio; Calabrese, Giovanna; Genovese, Carlo; Mastrojeni, Silvana; Ragusa, Salvatore; Acquaviva, Rosaria

2015-01-01

Tithonia diversifolia (Hemsl.) A. Gray (Asteraceae) is widely used in traditional medicine. There is increasing interest on the in vivo protective effects of natural compounds contained in plants against oxidative damage caused from reactive oxygen species. In the present study the total phenolic and flavonoid contents of aqueous, methanol and dichloromethane extracts of leaves of Tithonia diversifolia (Hemsl.) A. Gray were determined; furthermore, free radical scavenging capacity of each extract and the ability of these extracts to inhibit in vitro plasma lipid peroxidation were also evaluated. Since oxidative stress may be involved in trasformation of pre-adipocytes into adipocytes, to test the hypothesis that Tithonia extract may also affect adipocyte differentiation, human mesenchymal stem cell cultures were treated with Tithonia diversifolia aqueous extract and cell viability, free radical levels, Oil-Red O staining and western bolt analysis for heme oxygenase and 5'-adenosine monophoshate-activated protein kinase were carried out. Results obtained in the present study provide evidence that Tithonia diversifolia (Hemsl.) A. Gray exhibits interesting health promoting properties, resulting both from its free radical scavenger capacity and also by induction of protective cellular systems involved in cellular stress defenses and in adipogenesis of mesenchymal cells. PMID:25848759

Identification of Regulatory Elements That Control PPARγ Expression in Adipocyte Progenitors

PubMed Central

Chou, Wen-Ling; Galmozzi, Andrea; Partida, David; Kwan, Kevin; Yeung, Hui; Su, Andrew I.; Saez, Enrique

2013-01-01

Adipose tissue renewal and obesity-driven expansion of fat cell number are dependent on proliferation and differentiation of adipose progenitors that reside in the vasculature that develops in coordination with adipose depots. The transcriptional events that regulate commitment of progenitors to the adipose lineage are poorly understood. Because expression of the nuclear receptor PPARγ defines the adipose lineage, isolation of elements that control PPARγ expression in adipose precursors may lead to discovery of transcriptional regulators of early adipocyte determination. Here, we describe the identification and validation in transgenic mice of 5 highly conserved non-coding sequences from the PPARγ locus that can drive expression of a reporter gene in a manner that recapitulates the tissue-specific pattern of PPARγ expression. Surprisingly, these 5 elements appear to control PPARγ expression in adipocyte precursors that are associated with the vasculature of adipose depots, but not in mature adipocytes. Characterization of these five PPARγ regulatory sequences may enable isolation of the transcription factors that bind these cis elements and provide insight into the molecular regulation of adipose tissue expansion in normal and pathological states. PMID:24009687

Different anti-adipogenic effects of bio-compounds on primary visceral pre-adipocytes and adipocytes

PubMed Central

Colitti, Monica; Stefanon, Bruno

2016-01-01

Several natural compounds exhibit strong capacity for decreasing triglyceride accumulation, enhancing lipolysis and inducing apoptosis. The present study reports the anti-adipogenic effects of Silybum marianum (SL), Citrus aurantium (CA), Taraxacum officinale (TO), resveratrol (RE), Curcuma longa (CU), caffeine (CF), oleuropein (OL) and docosahexaenoic acid (DHA) in reducing differentiation and increasing lipolysis and apoptosis. Analyses were performed on human primary visceral pre-adipocytes after 10 (P10) and 20 (P20) days of treatment during differentiation and on mature adipocytes after 7 days of treatment (A7). The percentage of apoptosis induced by TO extract in P10 and P20 cells was significantly higher than that induced by all other compounds and in CTRL cells. Triglyceride accumulation was significantly lower in cells treated with DHA, CF, RE in comparison to cells treated with OL and in CTRL cells. Treatments with CF, DHA and OL significantly incremented lipolysis in P20 cells in comparison to other compounds and in CTRL cells. On the contrary, the treatment of A7 cells with OL, CA and TO compounds significantly increased cell lipolysis. The addition of CF in differentiating P20 pre-adipocytes significantly increased the expression of genes involved in inhibition of adipogenesis, such as GATA2, GATA3, WNT1, WNT3A, SFRP5, and DLK1. Genes involved in promoting adipogenesis such as CCND1, CEBPB and SREBF1 were significantly down-regulated by the treatment. The screening of bioactive compounds for anti-adipogenic effects showed that in differentiating cells TO extract was the most effective in inducing apoptosis and CF and DHA extracts were more efficient in inhibition of differentiation and in induction of cell lipolysis. PMID:27540349

FTO Obesity Variant Circuitry and Adipocyte Browning in Humans.

PubMed

Claussnitzer, Melina; Dankel, Simon N; Kim, Kyoung-Han; Quon, Gerald; Meuleman, Wouter; Haugen, Christine; Glunk, Viktoria; Sousa, Isabel S; Beaudry, Jacqueline L; Puviindran, Vijitha; Abdennur, Nezar A; Liu, Jannel; Svensson, Per-Arne; Hsu, Yi-Hsiang; Drucker, Daniel J; Mellgren, Gunnar; Hui, Chi-Chung; Hauner, Hans; Kellis, Manolis

2015-09-03

Genomewide association studies can be used to identify disease-relevant genomic regions, but interpretation of the data is challenging. The FTO region harbors the strongest genetic association with obesity, yet the mechanistic basis of this association remains elusive. We examined epigenomic data, allelic activity, motif conservation, regulator expression, and gene coexpression patterns, with the aim of dissecting the regulatory circuitry and mechanistic basis of the association between the FTO region and obesity. We validated our predictions with the use of directed perturbations in samples from patients and from mice and with endogenous CRISPR-Cas9 genome editing in samples from patients. Our data indicate that the FTO allele associated with obesity represses mitochondrial thermogenesis in adipocyte precursor cells in a tissue-autonomous manner. The rs1421085 T-to-C single-nucleotide variant disrupts a conserved motif for the ARID5B repressor, which leads to derepression of a potent preadipocyte enhancer and a doubling of IRX3 and IRX5 expression during early adipocyte differentiation. This results in a cell-autonomous developmental shift from energy-dissipating beige (brite) adipocytes to energy-storing white adipocytes, with a reduction in mitochondrial thermogenesis by a factor of 5, as well as an increase in lipid storage. Inhibition of Irx3 in adipose tissue in mice reduced body weight and increased energy dissipation without a change in physical activity or appetite. Knockdown of IRX3 or IRX5 in primary adipocytes from participants with the risk allele restored thermogenesis, increasing it by a factor of 7, and overexpression of these genes had the opposite effect in adipocytes from nonrisk-allele carriers. Repair of the ARID5B motif by CRISPR-Cas9 editing of rs1421085 in primary adipocytes from a patient with the risk allele restored IRX3 and IRX5 repression, activated browning expression programs, and restored thermogenesis, increasing it by a factor of 7

Bone marrow adipocytes: a neglected target tissue for growth hormone.

PubMed

Gevers, Evelien F; Loveridge, Nigel; Robinson, Iain C A F

2002-10-01

Bone marrow (BM) contains numerous adipocytes. These share a common precursor with osteoblasts and chondrocytes, but their function is unknown. It is unclear what regulates the differentiation of these three different cell types, though their subsequent metabolic activity is under hormonal regulation. GH and estrogen stimulate bone growth and mineralization, by direct effects on chondrocytes and osteoblasts. GH also stimulates lipolysis in subcutaneous and visceral adipocytes. However, adipocytes in BM have largely been ignored as potential targets for GH or estrogen action. We have addressed this by measuring BM adipocyte number, perimeter and area as well as bone area and osteoblast activity in GH-deficient dwarf (dw/dw), normal, or ovariectomized (Ovx) rats, with or without GH, IGF-1, PTH, or estrogen treatment or high fat feeding. Marrow adipocyte numbers were increased 5-fold (P < 0.001) in dw/dw rats, and cell size was also increased by 20%. These values returned toward normal in dw/dw rats given GH but not when given IGF-1. Cancellous bone area and osteoblast number were significantly (P < 0.005) lower in dw/dw rats, though alkaline phosphatase (ALP) activity in individual osteoblasts was unchanged. GH treatment increased % osteoblast covered bone surface without affecting individual cell ALP activity. Ovariectomy in normal or dw/dw rats had no affect on marrow adipocyte number nor size, although estrogen treatment in ovariectomized (Ovx) normal rats did increase adipocyte number. Ovx decreased tibial cancellous bone area in normal rats (64%; P < 0.05) and decreased osteoblast ALP-activity (P < 0.01) but did not affect the percentage of osteoblast-covered bone surface. Estrogen replacement reversed these changes. While treatment with PTH by continuous sc infusion decreased cancellous bone (P < 0.05) and high fat feeding increased the size of BM adipocytes (P < 0.01), they did not affect BM adipocyte number. These results suggest that GH has a specific action

Initial differences in lipid processing leading to pig-and beef-derived mature adipocyte differentiation

USDA-ARS?s Scientific Manuscript database

Clonal cultures of pig-derived mature adipocytes are capable of dedifferentiating and forming proliferative-competent progeny cells in vitro. Initial lipid processing, is different to that observed in cultures of beef-derived adipocytes. Mature pig adipocytes extrude lipid before proliferation, wher...

Adipocytes properties and crosstalk with immune system in obesity-related inflammation.

PubMed

Maurizi, Giulia; Della Guardia, Lucio; Maurizi, Angela; Poloni, Antonella

2018-01-01

Obesity is a condition likely associated with several dysmetabolic conditions or worsening of cardiovascular and other chronic disturbances. A key role in this mechanism seem to be played by the onset of low-grade systemic inflammation, highlighting the importance of the interplay between adipocytes and immune system cells. Adipocytes express a complex and highly adaptive biological profile being capable to selectively activate different metabolic pathways in order to respond to environmental stimuli. It has been demonstrated how adipocytes, under appropriate stimulation, can easily differentiate and de-differentiate thereby converting themselves into different phenotypes according to metabolic necessities. Although underlying mechanisms are not fully understood, growing in adipocyte size and the inability of storing triglycerides under overfeeding conditions seem to be crucial for the switching to a dysfunctional metabolic profile, which is characterized by inflammatory and apoptotic pathways activation, and by the shifting to pro-inflammatory adipokines secretion. In obesity, changes in adipokines secretion along with adipocyte deregulation and fatty acids release into circulation contribute to maintain immune cells activation as well as their infiltration into regulatory organs. Over the well-established role of macrophages, recent findings suggest the involvement of new classes of immune cells such as T regulatory lymphocytes and neutrophils in the development inflammation and multi systemic worsening. Deeply understanding the pathways of adipocyte regulation and the de-differentiation process could be extremely useful for developing novel strategies aimed at curbing obesity-related inflammation and related metabolic disorders. © 2017 Wiley Periodicals, Inc.

Antioxidant, anti-adipocyte differentiation, antitumor activity and anthelmintic activities against Anisakis simplex and Hymenolepis nana of yakuchinone A from Alpinia oxyphylla

PubMed Central

2013-01-01

Background Alpinia oxyphylla is a common remedy in traditional Chinese medicine. Yakuchinone A is a major constituent of A. oxyphylla and exhibits anti-inflammatory, antitumor, antibacterial, and gastric protective activities. Methods Antioxidant and antitumor characteristics of yakuchinone A in skin cancer cells as well as novel mechanisms for the inhibition of adipocyte differentiation, cestocidal activities against Hymenolepis nana adults, and nematocidal activities against Anisakis simplex larvae are investigated. Results Yakuchinone A presents the ability of the removal of DPPH·and ABTS+ free radicals and inhibition of lipid peroxidation. Yakuchinone A suppresses intracellular lipid accumulation during adipocyte differentiation in 3 T3-L1 cells and the expressions of leptin and peroxisome proliferator-activated receptor γ (PPARγ). Yakuchinone A induces apoptosis and inhibits cell proliferation in skin cancer cells. The inhibition of cell growth by yakuchinone A is more significant for non-melanoma skin cancer (NMSC) cells than for melanoma (A375 and B16) and noncancerous (HaCaT and BNLCL2) cells. Treatment BCC cells with yakuchinone A shows down-regulation of Bcl-2, up-regulation of Bax, and an increase in cleavage poly (ADP-ribose) polymerase (PARP). This suggests that yakuchinone A induces BCC cells apoptosis through the Bcl-2-mediated signaling pathway. The anthelmintic activities of yakuchinone A for A. simplex are better than for H. nana. Conclusions In this work, yakuchinone A exhibits antioxidative properties, anti-adipocyte differentiation, antitumor activity, and anthelmintic activities against A. simplex and H. nana. PMID:24070160

Increased extracellular and intracellular Ca{sup 2+} lead to adipocyte accumulation in bone marrow stromal cells by different mechanisms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, Ryota, E-mail: hryota@juntendo.ac.jp; Katoh, Youichi, E-mail: katoyo@juntendo-urayasu.jp; Department of Cardiology, Juntendo University Faculty of Medicine, Hongo 2-1-1, Bunkyo-ku, Tokyo 113-8421

2015-02-20

Mesenchymal stem cells found in bone marrow stromal cells (BMSCs) are the common progenitors for both adipocyte and osteoblast. An increase in marrow adipogenesis is associated with age-related osteopenia and anemia. Both extracellular and intracellular Ca{sup 2+} ([Ca{sup 2+}]{sub o} and [Ca{sup 2+}]{sub i}) are versatile signaling molecules that are involved in the regulation of cell functions, including proliferation and differentiation. We have recently reported that upon treatment of BMSCs with insulin and dexamethasone, both high [Ca{sup 2+}]{sub o} and high [Ca{sup 2+}]{sub i} enhanced adipocyte accumulation, which suggested that increases in [Ca{sup 2+}]{sub o} caused by bone resorption maymore » accelerate adipocyte accumulation in aging and diabetic patients. In this study, we used primary mouse BMSCs to investigate the mechanisms by which high [Ca{sup 2+}]{sub o} and high [Ca{sup 2+}]{sub i} may enhance adipocyte accumulation. In the process of adipocyte accumulation, two important keys are adipocyte differentiation and the proliferation of BMSCs, which have the potential to differentiate into adipocytes. Use of MTT assay and real-time RT-PCR revealed that high [Ca{sup 2+}]{sub i} (ionomycin)-dependent adipocyte accumulation is caused by enhanced proliferation of BMSCs but not enhanced differentiation into adipocytes. Using fura-2 fluorescence-based approaches, we showed that high [Ca{sup 2+}]{sub o} (addition of CaCl{sub 2}) leads to increases in [Ca{sup 2+}]{sub i}. Flow cytometric methods revealed that high [Ca{sup 2+}]{sub o} suppressed the phosphorylation of ERK independently of intracellular Ca{sup 2+}. The inhibition of ERK by U0126 and PD0325901 enhanced the differentiation of BMSCs into adipocytes. These data suggest that increased extracellular Ca{sup 2+} provides the differentiation of BMSCs into adipocytes by the suppression of ERK activity independently of increased intracellular Ca{sup 2+}, which results in BMSC proliferation

Dehydroepiandrosterone exerts antiglucocorticoid action on human preadipocyte proliferation, differentiation, and glucose uptake

PubMed Central

McNelis, Joanne C.; Manolopoulos, Konstantinos N.; Gathercole, Laura L.; Bujalska, Iwona J.; Stewart, Paul M.; Tomlinson, Jeremy W.

2013-01-01

Glucocorticoids increase adipocyte proliferation and differentiation, a process underpinned by the local reactivation of inactive cortisone to active cortisol within adipocytes catalyzed by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The adrenal sex steroid precursor dehydroepiandrosterone (DHEA) has been shown to inhibit 11β-HSD1 in murine adipocytes; however, rodent adrenals do not produce DHEA physiologically. Here, we aimed to determine the effects and underlying mechanisms of the potential antiglucocorticoid action of DHEA and its sulfate ester DHEAS in human preadipocytes. Utilizing a human subcutaneous preadipocyte cell line, Chub-S7, we examined the metabolism and effects of DHEA in human adipocytes, including adipocyte proliferation, differentiation, 11β-HSD1 expression, and activity and glucose uptake. DHEA, but not DHEAS, significantly inhibited preadipocyte proliferation via cell cycle arrest in the G1 phase independent of sex steroid and glucocorticoid receptor activation. 11β-HSD1 oxoreductase activity in differentiated adipocytes was inhibited by DHEA. DHEA coincubated with cortisone significantly inhibited preadipocyte differentiation, which was assessed by the expression of markers of early (LPL) and terminal (G3PDH) adipocyte differentiation. Coincubation with cortisol, negating the requirement for 11β-HSD1 oxoreductase activity, diminished the inhibitory effect of DHEA. Further consistent with glucocorticoid-opposing effects of DHEA, insulin-independent glucose uptake was significantly enhanced by DHEA treatment. DHEA increases basal glucose uptake and inhibits human preadipocyte proliferation and differentiation, thereby exerting an antiglucocorticoid action. DHEA inhibition of the amplification of glucocorticoid action mediated by 11β-HSD1 contributes to the inhibitory effect of DHEA on human preadipocyte differentiation. PMID:24022868

Identification of adipocyte adhesion molecule (ACAM), a novel CTX gene family, implicated in adipocyte maturation and development of obesity

PubMed Central

2004-01-01

Few cell adhesion molecules have been reported to be expressed in mature adipocytes, and the significance of cell adhesion process in adipocyte biology is also unknown. In the present study, we identified ACAM (adipocyte adhesion molecule), a novel homologue of the CTX (cortical thymocyte marker in Xenopus) gene family. ACAM cDNA was isolated during PCR-based cDNA subtraction, and its mRNA was shown to be up-regulated in WATs (white adipose tissues) of OLETF (Otsuka Long–Evans Tokushima fatty) rats, an animal model for Type II diabetes and obesity. ACAM, 372 amino acids in total, has a signal peptide, V-type (variable) and C2-type (constant) Ig domains, a single transmembrane segment and a cytoplasmic tail. The amino acid sequence in rat is highly homologous to mouse (94%) and human (87%). ACAM mRNA was predominantly expressed in WATs in OLETF rats, and increased with the development of obesity until 30 weeks of age, which is when the peak of body mass is reached. Western blot analysis revealed that ACAM protein, approx. 45 kDa, was associated with plasma membrane fractions of mature adipocytes isolated from mesenteric and subdermal adipose deposits of OLETF rats. Up-regulation of ACAM mRNAs in obesity was also shown in WATs of genetically obese db/db mice, diet-induced obese ICR mice and human obese subjects. In primary cultured mouse and human adipocytes, ACAM mRNA expression was progressively up-regulated during differentiation. Several stably transfected Chinese-hamster ovary K1 cell lines were established, and the quantification of ACAM mRNA and cell aggregation assay revealed that the degree of homophilic aggregation correlated well with ACAM mRNA expression. In summary, ACAM may be the critical adhesion molecule in adipocyte differentiation and development of obesity. PMID:15563274

Form(ul)ation of adipocytes by lipids.

PubMed

Lapid, Kfir; Graff, Jonathan M

2017-07-03

Lipids have the potential to serve as bio-markers, which allow us to analyze and to identify cells under various experimental settings, and to serve as a clinical diagnostic tool. For example, diagnosis according to specific lipids that are associated with diabetes and obesity. The rapid development of mass-spectrometry techniques enables identification and profiling of multiple types of lipid species. Together, lipid profiling and data interpretation forge the new field of lipidomics. Lipidomics can be used to characterize physiologic and pathophysiological processes in adipocytes, since lipid metabolism is at the core of adipocyte physiology and energy homeostasis. A significant bulk of lipids are stored in adipocytes, which can be released and used to produce energy, used to build membranes, or used as signaling molecules that regulate metabolism. In this review, we discuss how exhaust of lipidomes can be used to study adipocyte differentiation, physiology and pathophysiology.

Characterization of immortalized human brown and white pre-adipocyte cell models from a single donor

PubMed Central

Andersen, Elise S.; Rasmussen, Nanna E.; Petersen, Louise I.; Pedersen, Steen B.; Richelsen, Bjørn

2017-01-01

Brown adipose tissue with its constituent brown adipocytes is a promising therapeutic target in metabolic disorders due to its ability to dissipate energy and improve systemic insulin sensitivity and glucose homeostasis. The molecular control of brown adipocyte differentiation and function has been extensively studied in mice, but relatively little is known about such regulatory mechanisms in humans, which in part is due to lack of human brown adipose tissue derived cell models. Here, we used retrovirus-mediated overexpression to stably integrate human telomerase reverse transcriptase (TERT) into stromal-vascular cell fractions from deep and superficial human neck adipose tissue biopsies from the same donor. The brown and white pre-adipocyte cell models (TERT-hBA and TERT-hWA, respectively) displayed a stable proliferation rate and differentiation until at least passage 20. Mature TERT-hBA adipocytes expressed higher levels of thermogenic marker genes and displayed a higher maximal respiratory capacity than mature TERT-hWA adipocytes. TERT-hBA adipocytes were UCP1-positive and responded to β-adrenergic stimulation by activating the PKA-MKK3/6-p38 MAPK signaling module and increasing thermogenic gene expression and oxygen consumption. Mature TERT-hWA adipocytes underwent efficient rosiglitazone-induced ‘browning’, as demonstrated by strongly increased expression of UCP1 and other brown adipocyte-enriched genes. In summary, the TERT-hBA and TERT-hWA cell models represent useful tools to obtain a better understanding of the molecular control of human brown and white adipocyte differentiation and function as well as of browning of human white adipocytes. PMID:28957413

Obestatin as a regulator of adipocyte metabolism and adipogenesis

PubMed Central

Gurriarán-Rodríguez, Uxía; Al-Massadi, Omar; Roca-Rivada, Arturo; Crujeiras, Ana Belén; Gallego, Rosalía; Pardo, Maria; Seoane, Luisa Maria; Pazos, Yolanda; Casanueva, Felipe F; Camiña, Jesús P

2011-01-01

Abstract The role of obestatin, a 23-amino-acid peptide encoded by the ghrelin gene, on the control of the metabolism of pre-adipocyte and adipocytes as well as on adipogenesis was determined. For in vitro assays, pre-adipocyte and adipocyte 3T3-L1 cells were used to assess the obestatin effect on cell metabolism and adipogenesis based on the regulation of the key enzymatic nodes, Akt and AMPK and their downstream targets. For in vivo assays, white adipose tissue (WAT) was obtained from male rats under continuous subcutaneous infusion of obestatin. Obestatin activated Akt and its downstream targets, GSK3α/β, mTOR and S6K1, in 3T3-L1 adipocyte cells. Simultaneously, obestatin inactivated AMPK in this cell model. In keeping with this, ACC phosphorylation was also decreased. This fact was confirmed in vivo in white adipose tissue (omental, subcutaneous and gonadal) obtained from male rats under continuous sc infusion of obestatin (24 and 72 hrs). The relevance of obestatin as regulator of adipocyte metabolism was supported by AS160 phosphorylation, GLUT4 translocation and augment of glucose uptake in 3T3-L1 adipocyte cells. In contrast, obestatin failed to modify translocation of fatty acid transporters, FATP1, FATP4 and FAT/CD36, to plasma membrane. Obestatin treatment in combination with IBMX and DEX showed to regulate the expression of C/EBPα, C/EBPβ, C/EBPδ and PPARγ promoting adipogenesis. Remarkable, preproghrelin expression, and thus obestatin expression, increased during adipogenesis being sustained throughout terminal differentiation. Neutralization of endogenous obestatin secreted by 3T3-L1 cells by anti-obestatin antibody decreased adipocyte differentiation. Furthermore, knockdown experiments by preproghrelin siRNA supported that obestatin contributes to adipogenesis. In summary, obestatin promotes adipogenesis in an autocrine/paracrine manner, being a regulator of adipocyte metabolism. These data point to a putative role in the pathogenesis of

The human lipodystrophy gene product Berardinelli-Seip congenital lipodystrophy 2/seipin plays a key role in adipocyte differentiation.

PubMed

Chen, Weiqin; Yechoor, Vijay K; Chang, Benny Hung-Junn; Li, Ming V; March, Keith L; Chan, Lawrence

2009-10-01

Mutations in the Berardinelli-Seip congenital lipodystrophy 2 gene (BSCL2) are the underlying defect in patients with congenital generalized lipodystrophy type 2. BSCL2 encodes a protein called seipin, whose function is largely unknown. In this study, we investigated the role of Bscl2 in the regulation of adipocyte differentiation. Bscl2 mRNA is highly up-regulated during standard hormone-induced adipogenesis in 3T3-L1 cells in vitro. However, this up-regulation does not occur during mesenchymal stem cell (C3H10T1/2 cells) commitment to the preadipocyte lineage. Knockdown of Bscl2 by short hairpin RNA in C3H10T1/2 cells has no effect on bone morphogenetic protein-4-induced preadipocyte commitment. However, knockdown in 3T3-L1 cells prevents adipogenesis induced by a standard hormone cocktail, but adipogenesis can be rescued by the addition of peroxisome proliferator-activated receptor-gamma agonist pioglitazone at an early stage of differentiation. Interestingly, pioglitazone-induced differentiation in the absence of standard hormone is not associated with up-regulated Bscl2 expression. On the other hand, short hairpin RNA-knockdown of Bscl2 largely blocks pioglitazone-induced adipose differentiation. These experiments suggest that Bscl2 may be essential for normal adipogenesis; it works upstream or at the level of peroxisome proliferator-activated receptor-gamma, enabling the latter to exert its full activity during adipogenesis. Loss of Bscl2 function thus interferes with the normal transcriptional cascade of adipogenesis during fat cell differentiation, resulting in near total loss of fat or lipodystrophy.

Redundant roles of the phosphatidate phosphatase family in triacylglycerol synthesis in human adipocytes.

PubMed

Temprano, Ana; Sembongi, Hiroshi; Han, Gil-Soo; Sebastián, David; Capellades, Jordi; Moreno, Cristóbal; Guardiola, Juan; Wabitsch, Martin; Richart, Cristóbal; Yanes, Oscar; Zorzano, Antonio; Carman, George M; Siniossoglou, Symeon; Miranda, Merce

2016-09-01

In mammals, the evolutionary conserved family of Mg(2+)-dependent phosphatidate phosphatases (PAP1), involved in phospholipid and triacylglycerol synthesis, consists of lipin-1, lipin-2 and lipin-3. While mutations in the murine Lpin1 gene cause lipodystrophy and its knockdown in mouse 3T3-L1 cells impairs adipogenesis, deleterious mutations of human LPIN1 do not affect adipose tissue distribution. However, reduced LPIN1 and PAP1 activity has been described in participants with type 2 diabetes. We aimed to characterise the roles of all lipin family members in human adipose tissue and adipogenesis. The expression of the lipin family was analysed in adipose tissue in a cross-sectional study. Moreover, the effects of lipin small interfering RNA (siRNA)-mediated depletion on in vitro human adipogenesis were assessed. Adipose tissue gene expression of the lipin family is altered in type 2 diabetes. Depletion of every lipin family member in a human Simpson-Golabi-Behmel syndrome (SGBS) pre-adipocyte cell line, alters expression levels of adipogenic transcription factors and lipid biosynthesis genes in early stages of differentiation. Lipin-1 knockdown alone causes a 95% depletion of PAP1 activity. Despite the reduced PAP1 activity and alterations in early adipogenesis, lipin-silenced cells differentiate and accumulate neutral lipids. Even combinatorial knockdown of lipins shows mild effects on triacylglycerol accumulation in mature adipocytes. Overall, our data support the hypothesis of alternative pathways for triacylglycerol synthesis in human adipocytes under conditions of repressed lipin expression. We propose that induction of alternative lipid phosphate phosphatases, along with the inhibition of lipid hydrolysis, contributes to the maintenance of triacylglycerol content to near normal levels.

PCB-153 Shows Different Dynamics of Mobilisation from Differentiated Rat Adipocytes during Lipolysis in Comparison with PCB-28 and PCB-118

PubMed Central

Louis, Caroline; Tinant, Gilles; Mignolet, Eric; Thomé, Jean-Pierre; Debier, Cathy

2014-01-01

Background Polychlorinated biphenyls (PCBs) are persistent organic pollutants. Due to their lipophilic character, they are preferentially stored within the adipose tissue. During the mobilisation of lipids, PCBs might be released from adipocytes into the bloodstream. However, the mechanisms associated with the release of PCBs have been poorly studied. Several in vivo studies followed their dynamics of release but the complexity of the in vivo situation, which is characterised by a large range of pollutants, does not allow understanding precisely the behaviour of individual congeners. The present in vitro experiment studied the impact of (i) the number and position of chlorine atoms of PCBs on their release from adipocytes and (ii) the presence of other PCB congeners on the mobilisation rate of such molecules. Methodology/Principal Findings Differentiated rat adipocytes were used to compare the behaviour of PCB-28, -118 and -153. Cells were contaminated with the three congeners, alone or in cocktail, and a lipolysis was then induced with isoproterenol during 12 hours. Our data indicate that the three congeners were efficiently released from adipocytes and accumulated in the medium during the lipolysis. Interestingly, for a same level of cell lipids, PCB-153, a hexa-CB with two chlorine atoms in ortho-position, was mobilised slower than PCB-28, a tri-CB, and PCB-118, a penta-CB, which are both characterised by one chlorine atom in ortho-position. It suggests an impact of the chemical properties of pollutants on their mobilisation during periods of negative energy balance. Moreover, the mobilisation of PCB congeners, taken individually, did not seem to be influenced by the presence of other congeners within adipocytes. Conclusion/Significance These results not only highlight the obvious mobilisation of PCBs from adipocytes during lipolysis, in parallel to lipids, but also demonstrate that the structure of congeners defines their rate of release from adipocytes. PMID

PCB-153 shows different dynamics of mobilisation from differentiated rat adipocytes during lipolysis in comparison with PCB-28 and PCB-118.

PubMed

Louis, Caroline; Tinant, Gilles; Mignolet, Eric; Thomé, Jean-Pierre; Debier, Cathy

2014-01-01

Polychlorinated biphenyls (PCBs) are persistent organic pollutants. Due to their lipophilic character, they are preferentially stored within the adipose tissue. During the mobilisation of lipids, PCBs might be released from adipocytes into the bloodstream. However, the mechanisms associated with the release of PCBs have been poorly studied. Several in vivo studies followed their dynamics of release but the complexity of the in vivo situation, which is characterised by a large range of pollutants, does not allow understanding precisely the behaviour of individual congeners. The present in vitro experiment studied the impact of (i) the number and position of chlorine atoms of PCBs on their release from adipocytes and (ii) the presence of other PCB congeners on the mobilisation rate of such molecules. Differentiated rat adipocytes were used to compare the behaviour of PCB-28, -118 and -153. Cells were contaminated with the three congeners, alone or in cocktail, and a lipolysis was then induced with isoproterenol during 12 hours. Our data indicate that the three congeners were efficiently released from adipocytes and accumulated in the medium during the lipolysis. Interestingly, for a same level of cell lipids, PCB-153, a hexa-CB with two chlorine atoms in ortho-position, was mobilised slower than PCB-28, a tri-CB, and PCB-118, a penta-CB, which are both characterised by one chlorine atom in ortho-position. It suggests an impact of the chemical properties of pollutants on their mobilisation during periods of negative energy balance. Moreover, the mobilisation of PCB congeners, taken individually, did not seem to be influenced by the presence of other congeners within adipocytes. These results not only highlight the obvious mobilisation of PCBs from adipocytes during lipolysis, in parallel to lipids, but also demonstrate that the structure of congeners defines their rate of release from adipocytes.

De novo synthesis of steroids and oxysterols in adipocytes.

PubMed

Li, Jiehan; Daly, Edward; Campioli, Enrico; Wabitsch, Martin; Papadopoulos, Vassilios

2014-01-10

Local production and action of cholesterol metabolites such as steroids or oxysterols within endocrine tissues are currently recognized as an important principle in the cell type- and tissue-specific regulation of hormone effects. In adipocytes, one of the most abundant endocrine cells in the human body, the de novo production of steroids or oxysterols from cholesterol has not been examined. Here, we demonstrate that essential components of cholesterol transport and metabolism machinery in the initial steps of steroid and/or oxysterol biosynthesis pathways are present and active in adipocytes. The ability of adipocyte CYP11A1 in producing pregnenolone is demonstrated for the first time, rendering adipocyte a steroidogenic cell. The oxysterol 27-hydroxycholesterol (27HC), synthesized by the mitochondrial enzyme CYP27A1, was identified as one of the major de novo adipocyte products from cholesterol and its precursor mevalonate. Inhibition of CYP27A1 activity or knockdown and deletion of the Cyp27a1 gene induced adipocyte differentiation, suggesting a paracrine or autocrine biological significance for the adipocyte-derived 27HC. These findings suggest that the presence of the 27HC biosynthesis pathway in adipocytes may represent a defense mechanism to prevent the formation of new fat cells upon overfeeding with dietary cholesterol.

De Novo Synthesis of Steroids and Oxysterols in Adipocytes*

PubMed Central

Li, Jiehan; Daly, Edward; Campioli, Enrico; Wabitsch, Martin; Papadopoulos, Vassilios

2014-01-01

Local production and action of cholesterol metabolites such as steroids or oxysterols within endocrine tissues are currently recognized as an important principle in the cell type- and tissue-specific regulation of hormone effects. In adipocytes, one of the most abundant endocrine cells in the human body, the de novo production of steroids or oxysterols from cholesterol has not been examined. Here, we demonstrate that essential components of cholesterol transport and metabolism machinery in the initial steps of steroid and/or oxysterol biosynthesis pathways are present and active in adipocytes. The ability of adipocyte CYP11A1 in producing pregnenolone is demonstrated for the first time, rendering adipocyte a steroidogenic cell. The oxysterol 27-hydroxycholesterol (27HC), synthesized by the mitochondrial enzyme CYP27A1, was identified as one of the major de novo adipocyte products from cholesterol and its precursor mevalonate. Inhibition of CYP27A1 activity or knockdown and deletion of the Cyp27a1 gene induced adipocyte differentiation, suggesting a paracrine or autocrine biological significance for the adipocyte-derived 27HC. These findings suggest that the presence of the 27HC biosynthesis pathway in adipocytes may represent a defense mechanism to prevent the formation of new fat cells upon overfeeding with dietary cholesterol. PMID:24280213

Role of physiological levels of 4-hydroxynonenal on adipocyte biology: implications for obesity and metabolic syndrome.

PubMed

Dasuri, Kalavathi; Ebenezer, Philip; Fernandez-Kim, Sun Ok; Zhang, Le; Gao, Zhanguo; Bruce-Keller, Annadora J; Freeman, Linnea R; Keller, Jeffrey N

2013-01-01

Lipid peroxidation products such as 4-hydroxynonenal (HNE) are known to be increased in response to oxidative stress, and are known to cause dysfunction and pathology in a variety of tissues during periods of oxidative stress. The aim of the current study was to determine the chronic (repeated HNE exposure) and acute effects of physiological concentrations of HNE toward multiple aspects of adipocyte biology using differentiated 3T3-L1 adipocytes. Our studies demonstrate that acute and repeated exposure of adipocytes to physiological concentrations of HNE is sufficient to promote subsequent oxidative stress, impaired adipogenesis, alter the expression of adipokines, and increase lipolytic gene expression and subsequent increase in free fatty acid (FFA) release. These results provide an insight in to the role of HNE-induced oxidative stress in regulation of adipocyte differentiation and adipose dysfunction. Taken together, these data indicate a potential role for HNE promoting diverse effects toward adipocyte homeostasis and adipocyte differentiation, which may be important to the pathogenesis observed in obesity and metabolic syndrome.

The use of small interfering RNAs to inhibit adipocyte differentiation in human preadipocytes and fetal-femur-derived mesenchymal cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Y.; Mirmalek-Sani, S.-H.; Yang, X.

2006-06-10

RNA interference (RNAi) has been used in functional genomics and offers innovative approaches in the development of novel therapeutics. Human mesenchymal stem cells offer a unique cell source for tissue engineering/regeneration strategies. The current study examined the potential of small interfering RNAs (siRNA) against human peroxisome proliferator activated receptor gamma (PPAR{gamma}) to suppress adipocyte differentiation (adipogenesis) in human preadipocytes and fetal-femur-derived mesenchymal cells. Adipogenesis was investigated using cellular and biochemical analysis. Transient transfection with PPAR{gamma}-siRNA using a liposomal-based strategy resulted in a significant inhibition of adipogenesis in human preadipocytes and fetal-femur-derived mesenchymal cells, compared to controls (cell, liposomal and negativemore » siRNA). The inhibitory effect of PPAR{gamma}-siRNA was supported by testing human PPAR{gamma} mRNA and adipogenic associated genes using reverse transcription polymerase chain reaction (RT-PCR) to adiponectin receptor 1 and 2 as well as examination of fatty acid binding protein 3 (FABP{sub 3}) expression, an adipocyte-specific marker. The current studies indicate that PPAR{gamma}-siRNA is a useful tool to study adipogenesis in human cells, with potential applications both therapeutic and in the elucidation of mesenchymal cell differentiation in the modulation of cell differentiation in human mesenchymal cells.« less

Multiplatform Metabolomics Investigation of Antiadipogenic Effects on 3T3-L1 Adipocytes by a Potent Diarylheptanoid.

PubMed

Du, Dan; Gu, Haiwei; Djukovic, Danijel; Bettcher, Lisa; Gong, Meng; Zheng, Wen; Hu, Liqiang; Zhang, Xinyu; Zhang, Renke; Wang, Dongfang; Raftery, Daniel

2018-06-01

Obesity is fast becoming a serious health problem worldwide. Of the many possible antiobesity strategies, one interesting approach focuses on blocking adipocyte differentiation and lipid accumulation to counteract the rise in fat storage. However, there is currently no drug available for the treatment of obesity that works by inhibiting adipocyte differentiation. Here we use a broad-based metabolomics approach to interrogate and better understand metabolic changes that occur during adipocyte differentiation. In particular, we focus on changes induced by the antiadipogenic diarylheptanoid, which was isolated from a traditional Chinese medicine Dioscorea zingiberensis and identified as (3 R,5 R)-3,5-dihydroxy-1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-heptane (1). Targeted aqueous metabolic profiling indicated that a total of 14 metabolites involved in the TCA cycle, glycolysis, amino acid metabolism, and purine catabolism participate in regulating energy metabolism, lipogenesis, and lipolysis in adipocyte differentiation and can be modulated by diarylheptanoid 1. As indicated by lipidomics analysis, diarylheptanoid 1 restored the quantity and degree of unsaturation of long-chain free fatty acids and restored the levels of 171 lipids mainly from 10 lipid classes in adipocytes. In addition, carbohydrate metabolism in diarylheptanoid-1-treated adipocytes further demonstrated the delayed differentiation process by flux analysis. Our results provide valuable information for further understanding the metabolic adjustment in adipocytes subjected to diarylheptanoid 1 treatment. Moreover, this study offers new insight into developing antiadipogenic leading compounds based on metabolomics.

Osteoblast-like MC3T3-E1 Cells Prefer Glycolysis for ATP Production but Adipocyte-like 3T3-L1 Cells Prefer Oxidative Phosphorylation.

PubMed

Guntur, Anyonya R; Gerencser, Akos A; Le, Phuong T; DeMambro, Victoria E; Bornstein, Sheila A; Mookerjee, Shona A; Maridas, David E; Clemmons, David E; Brand, Martin D; Rosen, Clifford J

2018-06-01

Mesenchymal stromal cells (MSCs) are early progenitors that can differentiate into osteoblasts, chondrocytes, and adipocytes. We hypothesized that osteoblasts and adipocytes utilize distinct bioenergetic pathways during MSC differentiation. To test this hypothesis, we compared the bioenergetic profiles of preosteoblast MC3T3-E1 cells and calvarial osteoblasts with preadipocyte 3T3L1 cells, before and after differentiation. Differentiated MC3T3-E1 osteoblasts met adenosine triphosphate (ATP) demand mainly by glycolysis with minimal reserve glycolytic capacity, whereas nondifferentiated cells generated ATP through oxidative phosphorylation. A marked Crabtree effect (acute suppression of respiration by addition of glucose, observed in both MC3T3-E1 and calvarial osteoblasts) and smaller mitochondrial membrane potential in the differentiated osteoblasts, particularly those incubated at high glucose concentrations, indicated a suppression of oxidative phosphorylation compared with nondifferentiated osteoblasts. In contrast, both nondifferentiated and differentiated 3T3-L1 adipocytes met ATP demand primarily by oxidative phosphorylation despite a large unused reserve glycolytic capacity. In sum, we show that nondifferentiated precursor cells prefer to use oxidative phosphorylation to generate ATP; when they differentiate to osteoblasts, they gain a strong preference for glycolytic ATP generation, but when they differentiate to adipocytes, they retain the strong preference for oxidative phosphorylation. Unique metabolic programming in mesenchymal progenitor cells may influence cell fate and ultimately determine the degree of bone formation and/or the development of marrow adiposity. © 2018 American Society for Bone and Mineral Research. © 2018 American Society for Bone and Mineral Research.

MicroRNA-188 regulates age-related switch between osteoblast and adipocyte differentiation

PubMed Central

Li, Chang-Jun; Cheng, Peng; Liang, Meng-Ke; Chen, Yu-Si; Lu, Qiong; Wang, Jin-Yu; Xia, Zhu-Ying; Zhou, Hou-De; Cao, Xu; Xie, Hui; Liao, Er-Yuan; Luo, Xiang-Hang

2015-01-01

Bone marrow mesenchymal stem cells (BMSCs) exhibit an age-dependent reduction in osteogenesis that is accompanied by an increased propensity toward adipocyte differentiation. This switch increases adipocyte numbers and decreases the number of osteoblasts, contributing to age-related bone loss. Here, we found that the level of microRNA-188 (miR-188) is markedly higher in BMSCs from aged compared with young mice and humans. Compared with control mice, animals lacking miR-188 showed a substantial reduction of age-associated bone loss and fat accumulation in bone marrow. Conversely, mice with transgenic overexpression of miR-188 in osterix+ osteoprogenitors had greater age-associated bone loss and fat accumulation in bone marrow relative to WT mice. Moreover, using an aptamer delivery system, we found that BMSC-specific overexpression of miR-188 in mice reduced bone formation and increased bone marrow fat accumulation. We identified histone deacetylase 9 (HDAC9) and RPTOR-independent companion of MTOR complex 2 (RICTOR) as the direct targets of miR-188. Notably, BMSC-specific inhibition of miR-188 by intra–bone marrow injection of aptamer-antagomiR-188 increased bone formation and decreased bone marrow fat accumulation in aged mice. Together, our results indicate that miR-188 is a key regulator of the age-related switch between osteogenesis and adipogenesis of BMSCs and may represent a potential therapeutic target for age-related bone loss. PMID:25751060

MicroRNA-188 regulates age-related switch between osteoblast and adipocyte differentiation.

PubMed

Li, Chang-Jun; Cheng, Peng; Liang, Meng-Ke; Chen, Yu-Si; Lu, Qiong; Wang, Jin-Yu; Xia, Zhu-Ying; Zhou, Hou-De; Cao, Xu; Xie, Hui; Liao, Er-Yuan; Luo, Xiang-Hang

2015-04-01

Bone marrow mesenchymal stem cells (BMSCs) exhibit an age-dependent reduction in osteogenesis that is accompanied by an increased propensity toward adipocyte differentiation. This switch increases adipocyte numbers and decreases the number of osteoblasts, contributing to age-related bone loss. Here, we found that the level of microRNA-188 (miR-188) is markedly higher in BMSCs from aged compared with young mice and humans. Compared with control mice, animals lacking miR-188 showed a substantial reduction of age-associated bone loss and fat accumulation in bone marrow. Conversely, mice with transgenic overexpression of miR-188 in osterix+ osteoprogenitors had greater age-associated bone loss and fat accumulation in bone marrow relative to WT mice. Moreover, using an aptamer delivery system, we found that BMSC-specific overexpression of miR-188 in mice reduced bone formation and increased bone marrow fat accumulation. We identified histone deacetylase 9 (HDAC9) and RPTOR-independent companion of MTOR complex 2 (RICTOR) as the direct targets of miR-188. Notably, BMSC-specific inhibition of miR-188 by intra-bone marrow injection of aptamer-antagomiR-188 increased bone formation and decreased bone marrow fat accumulation in aged mice. Together, our results indicate that miR-188 is a key regulator of the age-related switch between osteogenesis and adipogenesis of BMSCs and may represent a potential therapeutic target for age-related bone loss.

Phloretin promotes adipocyte differentiation in vitro and improves glucose homeostasis in vivo.

PubMed

Shu, Gang; Lu, Nai-Sheng; Zhu, Xiao-Tong; Xu, Yong; Du, Min-Qing; Xie, Qiu-Ping; Zhu, Can-Jun; Xu, Qi; Wang, Song-Bo; Wang, Li-Na; Gao, Ping; Xi, Qian-Yun; Zhang, Yong-Liang; Jiang, Qing-Yan

2014-12-01

Adipocyte dysfunction is associated with many metabolic diseases such as obesity, insulin resistance and diabetes. Previous studies found that phloretin promotes 3T3-L1 cells differentiation, but the underlying mechanisms for phloretin's effects on adipogenesis remain unclear. In this study, we demonstrated that phloretin enhanced the lipid accumulation in porcine primary adipocytes in a time-dependent manner. Furthermore, phloretin increased the utilization of glucose and nonesterified fatty acid, while it decreased the lactate output. Microarray analysis revealed that genes associated with peroxisome proliferator-activated receptor-γ (PPARγ), mitogen-activated protein kinase and insulin signaling pathways were altered in response to phloretin. We further confirmed that phloretin enhanced expression of PPARγ, CAAT enhancer binding protein-α (C/EBPα) and adipose-related genes, such as fatty acids translocase and fatty acid synthase. In addition, phloretin activated the Akt (Thr308) and extracellular signal-regulated kinase, and therefore, inactivated Akt targets protein. Wortmannin effectively blocked the effect of phloretin on Akt activity and the protein levels of PPARγ, C/EBPα and fatty acid binding protein-4 (FABP4/aP2). Oral administration of 5 or 10 mg/kg phloretin to C57BL BKS-DB mice significantly decreased the serum glucose level and improved glucose tolerance. In conclusion, phloretin promotes the adipogenesis of porcine primary preadipocytes through Akt-associated signaling pathway. These findings suggested that phloretin might be able to increase insulin sensitivity and alleviate the metabolic diseases. Copyright © 2014. Published by Elsevier Inc.

Epoxyeicosatrienoic Acids Regulate Adipocyte Differentiation of Mouse 3T3 Cells, Via PGC-1α Activation, Which Is Required for HO-1 Expression and Increased Mitochondrial Function

PubMed Central

Waldman, Maayan; Bellner, Lars; Vanella, Luca; Schragenheim, Joseph; Sodhi, Komal; Singh, Shailendra P.; Lin, Daohong; Lakhkar, Anand; Li, Jiangwei; Hochhauser, Edith; Arad, Michael; Darzynkiewicz, Zbigniew; Kappas, Atallah

2016-01-01

Epoxyeicosatrienoic acid (EET) contributes to browning of white adipose stem cells to ameliorate obesity/diabetes and insulin resistance. In the current study, we show that EET altered preadipocyte function, enhanced peroxisome proliferation-activated receptor γ coactivator α (PGC-1α) expression, and increased mitochondrial function in the 3T3-L1 preadipocyte subjected to adipogenesis. Cells treated with EET resulted in an increase, P < 0.05, in PGC-1α and a decrease in mitochondria-derived ROS (MitoSox), P < 0.05. The EET increase in heme oxygenase-1 (HO-1) levels is dependent on activation of PGC-1α as cells deficient in PGC-1α (PGC-1α knockout adipocyte cell) have an impaired ability to express HO-1, P < 0.02. Additionally, adipocytes treated with EET exhibited an increase in mitochondrial superoxide dismutase (SOD) in a PGC-1α-dependent manner, P < 0.05. The increase in PGC-1α was associated with an increase in β-catenin, P < 0.05, adiponectin expression, P < 0.05, and lipid accumulation, P < 0.02. EET decreased heme levels and mitochondria-derived ROS (MitoSox), P < 0.05, compared to adipocytes that were untreated. EET also decreased mesoderm-specific transcript (MEST) mRNA and protein levels (P < 0.05). Adipocyte secretion of EET act in an autocrine/paracrine manner to increase PGC-1α is required for activation of HO-1 expression. This is the first study to dissect the mechanism by which the antiadipogenic and anti-inflammatory lipid, EET, induces the PGC-1α signaling cascade and reprograms the adipocyte phenotype by regulating mitochondrial function and HO-1 expression, leading to an increase in healthy, that is, small, adipocytes and a decrease in adipocyte enlargement and terminal differentiation. This is manifested by an increase in mitochondrial function and an increase in the canonical Wnt signaling cascade during adipocyte proliferation and terminal differentiation. PMID:27224420

MCT1 and MCT4 Expression and Lactate Flux Activity Increase During White and Brown Adipogenesis and Impact Adipocyte Metabolism.

PubMed

Petersen, Charlotte; Nielsen, Mette D; Andersen, Elise S; Basse, Astrid L; Isidor, Marie S; Markussen, Lasse K; Viuff, Birgitte M; Lambert, Ian H; Hansen, Jacob B; Pedersen, Stine F

2017-10-12

Adipose tissue takes up glucose and releases lactate, thereby contributing significantly to systemic glucose and lactate homeostasis. This implies the necessity of upregulation of net acid and lactate flux capacity during adipocyte differentiation and function. However, the regulation of lactate- and acid/base transporters in adipocytes is poorly understood. Here, we tested the hypothesis that adipocyte thermogenesis, browning and differentiation are associated with an upregulation of plasma membrane lactate and acid/base transport capacity that in turn is important for adipocyte metabolism. The mRNA and protein levels of the lactate-H + transporter MCT1 and the Na + ,HCO 3 - cotransporter NBCe1 were upregulated in mouse interscapular brown and inguinal white adipose tissue upon cold induction of thermogenesis and browning. MCT1, MCT4, and NBCe1 were furthermore strongly upregulated at the mRNA and protein level upon differentiation of cultured pre-adipocytes. Adipocyte differentiation was accompanied by increased plasma membrane lactate flux capacity, which was reduced by MCT inhibition and by MCT1 knockdown. Finally, in differentiated brown adipocytes, glycolysis (assessed as ECAR), and after noradrenergic stimulation also oxidative metabolism (OCR), was decreased by MCT inhibition. We suggest that upregulation of MCT1- and MCT4-mediated lactate flux capacity and NBCe1-mediated HCO 3 - /pH homeostasis are important for the physiological function of mature adipocytes.

Hibernoma formation in transgenic mice and isolation of a brown adipocyte cell line expressing the uncoupling protein gene.

PubMed Central

Ross, S R; Choy, L; Graves, R A; Fox, N; Solevjeva, V; Klaus, S; Ricquier, D; Spiegelman, B M

1992-01-01

Transgenic mice were produced containing the adipocyte-specific regulatory region from the adipocyte P2 (aP2) gene linked to the simian virus 40 transforming genes. Most of the transgenic mice developed brown fat tumors (hibernomas) in their interscapular brown adipose tissue. Hibernoma formation was noticeable in some of the mice as early as 1 day after birth and most of the mice developed very large tumors by 1 month of age. All of the tumor tissue expressed the brown fat-specific uncoupling protein (UCP) gene as well as the aP2 gene. Several of the tumors have been used to establish cultured cell lines and at least one of these lines can be induced to differentiate into brown adipocytes. The cultured adipocytes express mRNA for UCP upon stimulation with N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate, norepinephrine, isoproterenol or D7114, a beta 3 adrenergic agonist. Thus, regulation of the key thermogenic gene UCP can now be studied in an established cell line. Images PMID:1323843

DGAT enzymes are required for triacylglycerol synthesis and lipid droplets in adipocytes.

PubMed

Harris, Charles A; Haas, Joel T; Streeper, Ryan S; Stone, Scot J; Kumari, Manju; Yang, Kui; Han, Xianlin; Brownell, Nicholas; Gross, Richard W; Zechner, Rudolf; Farese, Robert V

2011-04-01

The total contribution of the acyl CoA:diacylglycerol acyltransferase (DGAT) enzymes, DGAT1 and DGAT2, to mammalian triacylglycerol (TG) synthesis has not been determined. Similarly, whether DGAT enzymes are required for lipid droplet (LD) formation is unknown. In this study, we examined the requirement for DGAT enzymes in TG synthesis and LDs in differentiated adipocytes with genetic deletions of DGAT1 and DGAT2. Adipocytes with a single deletion of either enzyme were capable of TG synthesis and LD formation. In contrast, adipocytes with deletions of both DGATs were severely lacking in TG and did not have LDs, indicating that DGAT1 and DGAT2 account for nearly all TG synthesis in adipocytes and appear to be required for LD formation during adipogenesis. DGAT enzymes were not absolutely required for LD formation in mammalian cells, however; macrophages deficient in both DGAT enzymes were able to form LDs when incubated with cholesterol-rich lipoproteins. Although adipocytes lacking both DGATs had no TG or LDs, they were fully differentiated by multiple criteria. Our findings show that DGAT1 and DGAT2 account for the vast majority of TG synthesis in mice, and DGAT function is required for LDs in adipocytes, but not in all cell types.

Gene expression profiling in multipotent DFAT cells derived from mature adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ono, Hiromasa; Database Center for Life Science; Oki, Yoshinao

2011-04-15

Highlights: {yields} Adipocyte dedifferentiation is evident in a significant decrease in typical genes. {yields} Cell proliferation is strongly related to adipocyte dedifferentiation. {yields} Dedifferentiated adipocytes express several lineage-specific genes. {yields} Comparative analyses using publicly available datasets boost the interpretation. -- Abstract: Cellular dedifferentiation signifies the withdrawal of cells from a specific differentiated state to a stem cell-like undifferentiated state. However, the mechanism of dedifferentiation remains obscure. Here we performed comparative transcriptome analyses during dedifferentiation in mature adipocytes (MAs) to identify the transcriptional signatures of multipotent dedifferentiated fat (DFAT) cells derived from MAs. Using microarray systems, we explored similarly expressed asmore » well as significantly differentially expressed genes in MAs during dedifferentiation. This analysis revealed significant changes in gene expression during this process, including a significant reduction in expression of genes for lipid metabolism concomitantly with a significant increase in expression of genes for cell movement, cell migration, tissue developmental processes, cell growth, cell proliferation, cell morphogenesis, altered cell shape, and cell differentiation. Our observations indicate that the transcriptional signatures of DFAT cells derived from MAs are summarized in terms of a significant decrease in functional phenotype-related genes and a parallel increase in cell proliferation, altered cell morphology, and regulation of the differentiation of related genes. A better understanding of the mechanisms involved in dedifferentiation may enable scientists to control and possibly alter the plasticity of the differentiated state, which may lead to benefits not only in stem cell research but also in regenerative medicine.« less

Proteomic identification of fat-browning markers in cultured white adipocytes treated with curcumin.

PubMed

Kim, Sang Woo; Choi, Jae Heon; Mukherjee, Rajib; Hwang, Ki-Chul; Yun, Jong Won

2016-04-01

We previously reported that curcumin induces browning of primary white adipocytes via enhanced expression of brown adipocyte-specific genes. In this study, we attempted to identify target proteins responsible for this fat-browning effect by analyzing proteomic changes in cultured white adipocytes in response to curcumin treatment. To elucidate the role of curcumin in fat-browning, we conducted comparative proteomic analysis of primary adipocytes between control and curcumin-treated cells using two-dimensional electrophoresis combined with MALDI-TOF-MS. We also investigated fatty acid metabolic targets, mitochondrial biogenesis, and fat-browning-associated proteins using combined proteomic and network analyses. Proteomic analysis revealed that 58 protein spots from a total of 325 matched spots showed differential expression between control and curcumin-treated adipocytes. Using network analysis, most of the identified proteins were proven to be involved in various metabolic and cellular processes based on the PANTHER classification system. One of the most striking findings is that hormone-sensitive lipase (HSL) was highly correlated with main browning markers based on the STRING database. HSL and two browning markers (UCP1, PGC-1α) were co-immunoprecipitated with these markers, suggesting that HSL possibly plays a role in fat-browning of white adipocytes. Our results suggest that curcumin increased HSL levels and other browning-specific markers, suggesting its possible role in augmentation of lipolysis and suppression of lipogenesis by trans-differentiation from white adipocytes into brown adipocytes (beige).

3'-hydroxy-ε,ε-caroten-3-one inhibits the differentiation of 3T3-L1 cells to adipocytes.

PubMed

Kotake-Nara, Eiichi; Hase, Megumi; Kobayashi, Miyuki; Nagao, Akihiko

2016-01-01

An oxidative metabolite of lutein, 3'-hydroxy-ε,ε-caroten-3-one, inhibited the differentiation of 3T3-L1 cells to adipocytes and the subsequent triacylglycerol production, but lutein did not. The α,β-unsaturated carbonyl structure of 3'-hydroxy-ε,ε-caroten-3-one was considered to participate in the inhibitory effect, suggesting that this lutein metabolite has the potential to prevent metabolic syndrome.

DGAT enzymes are required for triacylglycerol synthesis and lipid droplets in adipocytes[S

PubMed Central

Harris, Charles A.; Haas, Joel T.; Streeper, Ryan S.; Stone, Scot J.; Kumari, Manju; Yang, Kui; Han, Xianlin; Brownell, Nicholas; Gross, Richard W.; Zechner, Rudolf; Farese, Robert V.

2011-01-01

The total contribution of the acyl CoA:diacylglycerol acyltransferase (DGAT) enzymes, DGAT1 and DGAT2, to mammalian triacylglycerol (TG) synthesis has not been determined. Similarly, whether DGAT enzymes are required for lipid droplet (LD) formation is unknown. In this study, we examined the requirement for DGAT enzymes in TG synthesis and LDs in differentiated adipocytes with genetic deletions of DGAT1 and DGAT2. Adipocytes with a single deletion of either enzyme were capable of TG synthesis and LD formation. In contrast, adipocytes with deletions of both DGATs were severely lacking in TG and did not have LDs, indicating that DGAT1 and DGAT2 account for nearly all TG synthesis in adipocytes and appear to be required for LD formation during adipogenesis. DGAT enzymes were not absolutely required for LD formation in mammalian cells, however; macrophages deficient in both DGAT enzymes were able to form LDs when incubated with cholesterol-rich lipoproteins. Although adipocytes lacking both DGATs had no TG or LDs, they were fully differentiated by multiple criteria. Our findings show that DGAT1 and DGAT2 account for the vast majority of TG synthesis in mice, and DGAT function is required for LDs in adipocytes, but not in all cell types. PMID:21317108

Actin depolymerization enhances adipogenic differentiation in human stromal stem cells.

PubMed

Chen, Li; Hu, Huimin; Qiu, Weimin; Shi, Kaikai; Kassem, Moustapha

2018-05-01

Human stromal stem cells (hMSCs) differentiate into adipocytes that play a role in skeletal tissue homeostasis and whole body energy metabolism. During adipocyte differentiation, hMSCs exhibit significant changes in cell morphology suggesting changes in cytoskeletal organization. Here, we examined the effect of direct modulation of actin microfilament dynamics on adipocyte differentiation. Stabilizing actin filaments in hMSCs by siRNA-mediated knock down of the two main actin depolymerizing factors (ADFs): Cofilin 1 (CFL1) and Destrin (DSTN) or treating the cells by Phalloidin reduced adipocyte differentiation as evidenced by decreased number of mature adipocytes and decreased adipocyte specific gene expression (ADIPOQ, LPL, PPARG, FABP4). In contrast, disruption of actin cytoskeleton by Cytochalasin D enhanced adipocyte differentiation. Follow up studies revealed that the effects of CFL1 on adipocyte differentiation depended on the activity of LIM domain kinase 1 (LIMK1) which is the major upstream kinase of CFL1. Inhibiting LIMK by its specific chemical inhibitor LIMKi inhibited the phosphorylation of CFL1 and actin polymerization, and enhanced the adipocyte differentiation. Moreover, treating hMSCs by Cytochalasin D inhibited ERK and Smad2 signaling and this was associated with enhanced adipocyte differentiation. On the other hand, Phalloidin enhanced ERK and Smad2 signaling, but inhibited adipocyte differentiation which was rescued by ERK specific chemical inhibitor U0126. Our data provide a link between restructuring of hMSCs cytoskeleton and hMSCs lineage commitment and differentiation. Copyright © 2018 Elsevier B.V. All rights reserved.

Caffeic Acid Phenethyl Ester Regulates PPAR's Levels in Stem Cells-Derived Adipocytes

PubMed Central

Vanella, Luca; Tibullo, Daniele; Godos, Justyna; Pluchinotta, Francesca Romana; Di Giacomo, Claudia; Sorrenti, Valeria; Acquaviva, Rosaria; Russo, Alessandra; Li Volti, Giovanni; Barbagallo, Ignazio

2016-01-01

Hypertrophic obesity inhibits activation of peroxisome proliferators-activated receptor gamma (PPARγ), considered the key mediator of the fully differentiated and insulin sensitive adipocyte phenotype. We examined the effects of Caffeic Acid Phenethyl Ester (Cape), isolated from propolis, a honeybee hive product, on Adipose Stem Cells (ASCs) differentiation to the adipocyte lineage. Finally we tested the effects of Cape on insulin-resistant adipocytes. Quantification of Oil Red O-stained cells showed that lipid droplets decreased following Cape treatment as well as radical oxygen species formation. Additionally, exposure of ASC to high glucose levels decreased adiponectin and increased proinflammatory cytokines mRNA levels, which were reversed by Cape-mediated increase of insulin sensitivity. Cape treatment resulted in decreased triglycerides synthesis and increased beta-oxidation. Exposure of ASCs to Lipopolysaccharide (LPS) induced a reduction of PPARγ, an increase of IL-6 levels associated with a well-known stimulation of lipolysis; Cape partially attenuated the LPS-mediated effects. These observations reveal the main role of PPARγ in the adipocyte function and during ASC differentiation. As there is now substantial interest in functional food and nutraceutical products, the observed therapeutic value of Cape in insulin-resistance related diseases should be taken into consideration. PMID:26904104

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle

PubMed Central

2010-01-01

Background The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. Methods For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Results Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated

Lotus leaf extract and L-carnitine influence different processes during the adipocyte life cycle.

PubMed

Siegner, Ralf; Heuser, Stefan; Holtzmann, Ursula; Söhle, Jörn; Schepky, Andreas; Raschke, Thomas; Stäb, Franz; Wenck, Horst; Winnefeld, Marc

2010-08-05

The cellular and molecular mechanisms of adipose tissue biology have been studied extensively over the last two decades. Adipose tissue growth involves both an increase in fat cell size and the formation of mature adipocytes from precursor cells. To investigate how natural substances influence these two processes, we examined the effects of lotus leaf extract (Nelumbo nucifera-extract solution obtained from Silab, France) and L-carnitine on human preadipocytes and adipocytes. For our in vitro studies, we used a lotus leaf extract solution alone or in combination with L-carnitine. Utilizing cultured human preadipocytes, we investigated lotus leaf extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. Studies on human adipocytes were performed aiming to elucidate the efficacy of lotus leaf extract solution to stimulate lipolytic activity. To further characterize lotus leaf extract solution-mediated effects, we determined the expression of the transcription factor adipocyte determination and differentiation factor 1 (ADD1/SREBP-1c) on the RNA- and protein level utilizing qRT-PCR and immunofluorescence analysis. Additionally, the effect of L-carnitine on beta-oxidation was analyzed using human preadipocytes and mature adipocytes. Finally, we investigated additive effects of a combination of lotus leaf extract solution and L-carnitine on triglyceride accumulation during preadipocyte/adipocyte differentiation. Our data showed that incubation of preadipocytes with lotus leaf extract solution significantly decreased triglyceride accumulation during adipogenesis without affecting cell viability. Compared to controls, adipocytes incubated with lotus leaf extract solution exhibited a significant increase in lipolysis-activity. Moreover, cell populations cultivated in the presence of lotus leaf extract solution showed a decrease in adipocyte differentiation capacity as indicated by a decrease in the ADD1

Trans-10,cis-12 conjugated linoleic acid (t10-c12 CLA) treatment and caloric restriction differentially affect adipocyte cell turnover in obese and lean mice.

PubMed

Yeganeh, Azadeh; Zahradka, Peter; Taylor, Carla G

2017-11-01

Caloric restriction (CR) is one of the most promising strategies for weight loss but is associated with loss of lean mass, whereas compounds such as trans-10,cis-12 conjugated linoleic acid (t10-c12 CLA) have been promoted as antiobesity agents. To compare the mechanisms of weight reduction by CR and t10-c12 CLA, body composition, glucose control, and characteristics of adipose tissue with respect to cell turnover (stem cells and preadipocytes, apoptosis and autophagy) and Tbx-1 localization were examined in obese db/db mice and lean C57BL/6J mice undergoing CR or fed CLA isomers (0.4% w/w c9-t11 or t10-c12) for 4 weeks. Our findings show that the t10-c12 CLA reduced whole-body fat mass by decreasing all fat depots (visceral, inguinal, brown/interscapular), while CR lowered both whole-body fat and lean mass in obese mice. t10-c12 CLA elevated blood glucose in both obese and lean mice, while glycemia was not altered by CR. The adipocyte stem cell population remained unchanged; however, t10-c12 CLA reduced and CR elevated the proportion of immature adipocytes in obese mice, suggesting differential effects on adipocyte maturation. t10-c12 CLA reduced apoptosis (activated caspase-3) in both obese and lean mice but did not alter autophagy (LC3II/LC3I). Nuclear Tbx-1, a marker of metabolically active beige adipocytes, was greater in the adipose of t10-c12 CLA-fed animals. Thus, weight loss achieved via t10-c12 CLA primarily involves fat loss and more cells with Tbx-1 localized to the nucleus, while CR operates through a mechanism that reduces both lean and fat mass and blocks adipocyte differentiation. Copyright © 2017 Elsevier Inc. All rights reserved.

Dose- and type-dependent effects of long-chain fatty acids on adipogenesis and lipogenesis of bovine adipocytes.

PubMed

Yanting, Chen; Yang, Q Y; Ma, G L; Du, M; Harrison, J H; Block, E

2018-02-01

Differentiation and lipid metabolism of adipocytes have a great influence on milk performance, health, and feed efficiency of dairy cows. The effects of dietary long-chain fatty acids (FA) on adipogenesis and lipogenesis of dairy cows are often confounded by other nutritional and physiological factors in vivo. Therefore, this study used an in vitro approach to study the effect of dose and type of long-chain FA on adipogenesis and lipogenesis of bovine adipocytes. Stromal vascular cells were isolated from adipose tissue of dairy cows and induced into mature adipocytes in the presence of various long-chain FA including myristic, palmitic, stearic, oleic, or linoleic acid. When concentrations of myristic, palmitic, and oleic acids in adipogenic mediums were 150 and 200 μM, the induced mature adipocytes had greater lipid content compared with other concentrations of FA. In addition, mature adipocytes induced at 100 μM stearic acid and 300 μM linoleic acid had the greatest content of lipid than at other concentrations. High concentrations of saturated FA were more toxic for cells than the same concentration of unsaturated FA during the induction. When commitment stage was solely treated with FA, the number of differentiated mature adipocytes was greater for oleic and linoleic acids than other FA. When the maturation stage was treated with FA, the number of mature adipocytes was not affected, but the lipid content in adipocytes was affected and ranked oleic > linoleic > myristic > stearic > palmitic. In summary, this study showed that adipogenesis and lipogenesis of bovine adipocytes were differentially affected by long-chain FA, with unsaturated FA more effective than saturated FA. Copyright © 2018 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Naringenin Inhibits Adipogenesis and Reduces Insulin Sensitivity and Adiponectin Expression in Adipocytes

PubMed Central

Richard, Allison J.; Ribnicky, David M.; Stephens, Jacqueline M.

2013-01-01

Adipose tissue development and function are widely studied to examine the relationship between obesity and the metabolic syndrome. It is well documented that the inability of adipose tissue to properly increase its lipid storage capacity during the obese state can lead to metabolic dysfunction. In a blind screen of 425 botanicals, we identified naringenin as an inhibitor of adipocyte differentiation. Naringenin is one of the most abundant citrus flavonoids, and recent studies have demonstrated antihyperlipidemic capabilities. These studies have largely focused on the effects of naringenin on the liver. Our biochemical studies clearly demonstrate that naringenin inhibits adipogenesis and impairs mature fat cell function. Naringenin specifically inhibited adipogenesis in a dose-dependent fashion as judged by examining lipid accumulation and induction of adipocyte marker protein expression. In mature 3T3-L1 adipocytes, naringenin reduced the ability of insulin to induce IRS-1 tyrosine phosphorylation and substantially inhibited insulin-stimulated glucose uptake in a dose-dependent manner and over a time frame of 1.5 to 24 hours. Exposure to naringenin also inhibited adiponectin protein expression in mature murine and human adipocytes. Our studies have revealed that naringenin may have a negative impact on adipocyte-related diseases by limiting differentiation of preadipocytes, by significantly inducing insulin resistance, and by decreasing adiponectin expression in mature fat cells. PMID:23983791

Ceiling culture of mature human adipocytes: use in studies of adipocyte functions.

PubMed

Zhang, H H; Kumar, S; Barnett, A H; Eggo, M C

2000-02-01

Adipocytes contain large lipid droplets in their cytoplasm. When cultured, they float on top of the medium, clump together, and do not gain equal and sufficient access to the medium. Morphological changes cannot be observed and the majority of adipocytes undergo cell lysis within 72 h of isolation. We have used a ceiling culture method for human mature adipocytes which uses their buoyant property to allow them to adhere to a floating glass surface, where they remain viable for several weeks. Using confocal immunofluorescence microscopy we showed the cellular expression and subcellular localization of leptin in ceiling-cultured adipocytes. The secretion of leptin was increased from ceiling cultures following tumour necrosis factor-alpha treatment. Proliferation of mature human adipocytes in serum-containing medium was demonstrated by incorporation of bromodeoxyuridine, 2% of adipocytes showing positive incorporation after 4 h labelling. Proliferation was also evident from the budding of daughter cells. Apoptosis in the ceiling cultures was increased by 48 h serum deprivation (30-35 vs 10-15% in the control) and was assayed by propidium iodide staining and terminal deoxynucleotidyl transferase-mediated dUTP-fluorescein nick-end labelling. Lipolysis, analysed by liquid scintillation counting, was increased by forskolin (10 microM for 90 min) and lipogenesis, shown by autoradiography, was stimulated by insulin (10 and 100 nM for 4 h). These findings indicate that ceiling-cultured adipocytes maintain adipocyte-specific functions and that ceiling culture, which overcomes the shortcomings of adipocyte suspension culture, can be used to study adipocyte cell biology.

Adaptor protein SH2-B linking receptor-tyrosine kinase and Akt promotes adipocyte differentiation by regulating peroxisome proliferator-activated receptor gamma messenger ribonucleic acid levels.

PubMed

Yoshiga, Daigo; Sato, Naoichi; Torisu, Takehiro; Mori, Hiroyuki; Yoshida, Ryoko; Nakamura, Seiji; Takaesu, Giichi; Kobayashi, Takashi; Yoshimura, Akihiko

2007-05-01

Adipocyte differentiation is regulated by insulin and IGF-I, which transmit signals by activating their receptor tyrosine kinase. SH2-B is an adaptor protein containing pleckstrin homology and Src homology 2 (SH2) domains that have been implicated in insulin and IGF-I receptor signaling. In this study, we found a strong link between SH2-B levels and adipogenesis. The fat mass and expression of adipogenic genes including peroxisome proliferator-activated receptor gamma (PPARgamma) were reduced in white adipose tissue of SH2-B-/- mice. Reduced adipocyte differentiation of SH2-B-deficient mouse embryonic fibroblasts (MEFs) was observed in response to insulin and dexamethasone, whereas retroviral SH2-B overexpression enhanced differentiation of 3T3-L1 preadipocytes to adipocytes. SH2-B overexpression enhanced mRNA level of PPARgamma in 3T3-L1 cells, whereas PPARgamma levels were reduced in SH2-B-deficient MEFs in response to insulin. SH2-B-mediated up-regulation of PPARgamma mRNA was blocked by a phosphatidylinositol 3-kinase inhibitor, but not by a MAPK kinase inhibitor. Insulin-induced Akt activation and the phosphorylation of forkhead transcription factor (FKHR/Foxo1), a negative regulator of PPARgamma transcription, were up-regulated by SH2-B overexpression, but reduced in SH2-B-deficient MEFs. These data indicate that SH2-B is a key regulator of adipogenesis both in vivo and in vitro by regulating the insulin/IGF-I receptor-Akt-Foxo1-PPARgamma pathway.

Multiethnic genome-wide meta-analysis of ectopic fat depots identifies loci associated with adipocyte development and differentiation.

PubMed

Chu, Audrey Y; Deng, Xuan; Fisher, Virginia A; Drong, Alexander; Zhang, Yang; Feitosa, Mary F; Liu, Ching-Ti; Weeks, Olivia; Choh, Audrey C; Duan, Qing; Dyer, Thomas D; Eicher, John D; Guo, Xiuqing; Heard-Costa, Nancy L; Kacprowski, Tim; Kent, Jack W; Lange, Leslie A; Liu, Xinggang; Lohman, Kurt; Lu, Lingyi; Mahajan, Anubha; O'Connell, Jeffrey R; Parihar, Ankita; Peralta, Juan M; Smith, Albert V; Zhang, Yi; Homuth, Georg; Kissebah, Ahmed H; Kullberg, Joel; Laqua, René; Launer, Lenore J; Nauck, Matthias; Olivier, Michael; Peyser, Patricia A; Terry, James G; Wojczynski, Mary K; Yao, Jie; Bielak, Lawrence F; Blangero, John; Borecki, Ingrid B; Bowden, Donald W; Carr, John Jeffrey; Czerwinski, Stefan A; Ding, Jingzhong; Friedrich, Nele; Gudnason, Vilmunder; Harris, Tamara B; Ingelsson, Erik; Johnson, Andrew D; Kardia, Sharon L R; Langefeld, Carl D; Lind, Lars; Liu, Yongmei; Mitchell, Braxton D; Morris, Andrew P; Mosley, Thomas H; Rotter, Jerome I; Shuldiner, Alan R; Towne, Bradford; Völzke, Henry; Wallaschofski, Henri; Wilson, James G; Allison, Matthew; Lindgren, Cecilia M; Goessling, Wolfram; Cupples, L Adrienne; Steinhauser, Matthew L; Fox, Caroline S

2017-01-01

Variation in body fat distribution contributes to the metabolic sequelae of obesity. The genetic determinants of body fat distribution are poorly understood. The goal of this study was to gain new insights into the underlying genetics of body fat distribution by conducting sample-size-weighted fixed-effects genome-wide association meta-analyses in up to 9,594 women and 8,738 men of European, African, Hispanic and Chinese ancestry, with and without sex stratification, for six traits associated with ectopic fat (hereinafter referred to as ectopic-fat traits). In total, we identified seven new loci associated with ectopic-fat traits (ATXN1, UBE2E2, EBF1, RREB1, GSDMB, GRAMD3 and ENSA; P < 5 × 10 -8 ; false discovery rate < 1%). Functional analysis of these genes showed that loss of function of either Atxn1 or Ube2e2 in primary mouse adipose progenitor cells impaired adipocyte differentiation, suggesting physiological roles for ATXN1 and UBE2E2 in adipogenesis. Future studies are necessary to further explore the mechanisms by which these genes affect adipocyte biology and how their perturbations contribute to systemic metabolic disease.

The Role of Paracrine and Autocrine Signaling in the Early Phase of Adipogenic Differentiation of Adipose-derived Stem Cells

PubMed Central

Hemmingsen, Mette; Vedel, Søren; Skafte-Pedersen, Peder; Sabourin, David; Collas, Philippe; Bruus, Henrik; Dufva, Martin

2013-01-01

Introduction High cell density is known to enhance adipogenic differentiation of mesenchymal stem cells, suggesting secretion of signaling factors or cell-contact-mediated signaling. By employing microfluidic biochip technology, we have been able to separate these two processes and study the secretion pathways. Methods and results Adipogenic differentiation of human adipose-derived stem cells (ASCs) cultured in a microfluidic system was investigated under perfusion conditions with an adipogenic medium or an adipogenic medium supplemented with supernatant from differentiating ASCs (conditioned medium). Conditioned medium increased adipogenic differentiation compared to adipogenic medium with respect to accumulation of lipid-filled vacuoles and gene expression of key adipogenic markers (C/EBPα, C/EBPβ, C/EBPδ, PPARγ, LPL and adiponectin). The positive effects of conditioned medium were observed early in the differentiation process. Conclusions Using different cell densities and microfluidic perfusion cell cultures to suppress the effects of cell-released factors, we have demonstrated the significant role played by auto- or paracrine signaling in adipocyte differentiation. The cell-released factor(s) were shown to act in the recruitment phase of the differentiation process. PMID:23723991

Differential association of S100A9, an inflammatory marker, and p53, a cell cycle marker, expression with epicardial adipocyte size in patients with cardiovascular disease.

PubMed

Agra, Rosa María; Fernández-Trasancos, Ángel; Sierra, Juan; González-Juanatey, José Ramón; Eiras, Sonia

2014-10-01

S100A9 (calgranulin B) has inflammatory and oxidative stress properties and was found to be associated with atherosclerosis and obesity. One of the proteins that can regulate S100A9 transcription is p53, which is involved in cell cycle, apoptosis and adipogenesis. Thus, it triggers adipocyte enlargement and finally obesity. Because epicardial adipose tissue (EAT) volume and thickness is related to coronary artery disease (CAD), we studied the gene expression of this pathway in patients with cardiovascular disease and its association with obesity. Adipocytes and stromal cells from EAT and subcutaneous adipose tissue (SAT) from 48 patients who underwent coronary artery bypass graft and/or valve replacement were obtained after collagenase digestion and differential centrifugation. The expression levels of the involved genes on adipogenesis and cell cycle like fatty acid-binding protein (FABP) 4, retinol-binding protein (RBP)4, p53 and S100A9 were determined by real-time polymerase chain reaction (PCR). Adipocyte diameter was measured by optical microscopy. We found that epicardial adipocytes expressed significantly lower levels of adipogenic genes (FABP4 and RBP4) and cell cycle-related genes (S100A9 and p53) than subcutaneous adipocytes. However, in obese patients, upregulation of adipogenic and cell cycle-related genes in subcutaneous and epicardial adipocytes, respectively, was observed. The enlargement of adipocyte size was related to FABP4, S100A9 and p53 expression levels in stromal cells. But only the p53 association was maintained in epicardial stromal cells from obese patients (p=0.003). The expression of p53, but not S100A9, in epicardial stromal cells is related to adipocyte enlargement in obese patients with cardiovascular disease. These findings suggest new mechanisms for understanding the relationship between epicardial fat thickness, obesity and cardiovascular disease.

Atypical antipsychotics induce both proinflammatory and adipogenic gene expression in human adipocytes in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sárvári, Anitta K., E-mail: anittasarvari@med.unideb.hu; Veréb, Zoltán, E-mail: jzvereb@gmail.com; Uray, Iván P., E-mail: ipuray@mdanderson.org

Highlights: • Antipsychotics modulate the expression of adipogenic genes in human adipocytes. • Secretion of proinflammatory cytokine IL8 and MCP-1 is induced by antipsychotics. • Adipocyte-dependent inflammatory abnormality could develop during chronic treatment. • Infiltrated macrophages would further enhance proinflammatory cytokine production. - Abstract: Schizophrenia requires lifelong treatment, potentially causing systemic changes in metabolic homeostasis. In the clinical setting, antipsychotic treatment may differentially lead to weight gain among individual patients, although the molecular determinants of such adverse effects are currently unknown. In this study, we investigated changes in the expression levels of critical regulatory genes of adipogenesis, lipid metabolism andmore » proinflammatory genes during the differentiation of primary human adipose-derived stem cells (ADSCs). These cells were isolated from patients with body mass indices <25 and treated with the second-generation antipsychotics olanzapine, ziprasidone, clozapine, quetiapine, aripiprazole and risperidone and the first-generation antipsychotic haloperidol. We found that antipsychotics exhibited a marked effect on key genes involved in the regulation of cell cycle, signal transduction, transcription factors, nuclear receptors, differentiation markers and metabolic enzymes. In particular, we observed an induction of the transcription factor NF-KB1 and NF-KB1 target genes in adipocytes in response to these drugs, including the proinflammatory cytokines TNF-α, IL-1β, IL-8 and MCP-1. In addition, enhanced secretion of both IL8 and MCP-1 was observed in the supernatant of these cell cultures. In addition to their remarkable stimulatory effects on proinflammatory gene transcription, three of the most frequently prescribed antipsychotic drugs, clozapine, quetiapine and aripiprazole, also induced the expression of essential adipocyte differentiation genes and the adipocyte hormones

11-Hydroxy-β-steroid dehydrogenase gene expression in canine adipose tissue and adipocytes: stimulation by lipopolysaccharide and tumor necrosis factor α.

PubMed

Ryan, V H; Trayhurn, P; Hunter, L; Morris, P J; German, A J

2011-10-01

The enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD-1) is expressed in a number of tissues in rodents and humans and is responsible for the reactivation of inert cortisone into cortisol. Its gene expression and activity are increased in white adipose tissue (WAT) from obese humans and may contribute to the adverse metabolic consequences of obesity and the metabolic syndrome. The extent to which 11β-HSD-1 contributes to adipose tissue function in dogs is unknown; the aim of the present study was to examine 11β-HSD-1 gene expression and its regulation by proinflammatory and anti-inflammatory agents in canine adipocytes. Real-time PCR was used to examine the expression of 11β-HSD-1 in canine adipose tissue and canine adipocytes differentiated in culture. The mRNA encoding 11β-HSD-1 was identified in all the major WAT depots in dogs and also in liver, kidney, and spleen. Quantification by real-time PCR showed that 11β-HSD-1 mRNA was least in perirenal and falciform depots and greatest in subcutaneous, omental, and gonadal depots. Greater expression was seen in the omental depot in female than in male dogs (P=0.05). Gene expression for 11β-HSD-1 was also seen in adipocytes, from both subcutaneous and visceral depots, differentiated in culture; expression was evident throughout differentiation but was generally greatest in preadipocytes and during early differentiation, declining as cells progressed to maturity. The inflammatory mediators lipopolysaccharide and tumor necrosis factor α had a main stimulatory effect on 11β-HSD-1 gene expression in canine subcutaneous adipocytes, but IL-6 had no significant effect. Treatment with dexamethasone resulted in a significant time- and dose-dependent increase in 11β-HSD-1 gene expression, with greatest effects seen at 24 h (2 nM: approximately 4-fold; 20 nM: approximately 14-fold; P=0.010 for both). When subcutaneous adipocytes were treated with the peroxisome proliferator activated receptor γ agonist rosiglitazone

Estrogen-related receptor {alpha} modulates the expression of adipogenesis-related genes during adipocyte differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ijichi, Nobuhiro; Ikeda, Kazuhiro; Horie-Inoue, Kuniko

2007-07-06

Estrogen-related receptor {alpha} (ERR{alpha}) is an orphan nuclear receptor that regulates cellular energy metabolism by modulating gene expression involved in fatty acid oxidation and mitochondrial biogenesis in brown adipose tissue. However, the physiological role of ERR{alpha} in adipogenesis and white adipose tissue development has not been well studied. Here, we show that ERR{alpha} and ERR{alpha}-related transcriptional coactivators, peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) coactivator-1{alpha} (PGC-1{alpha}) and PGC-1{beta}, can be up-regulated in 3T3-L1 preadipocytes at mRNA levels under the adipogenic differentiation condition including the inducer of cAMP, glucocorticoid, and insulin. Gene knockdown by ERR{alpha}-specific siRNA results in mRNA down-regulation of fatty acidmore » binding protein 4, PPAR{gamma}, and PGC-1{alpha} in 3T3-L1 cells in the adipogenesis medium. ERR{alpha} and PGC-1{beta} mRNA expression can be also up-regulated in another preadipocyte lineage DFAT-D1 cells and a pluripotent mesenchymal cell line C3H10T1/2 under the differentiation condition. Furthermore, stable expression of ERR{alpha} in 3T3-L1 cells up-regulates adipogenic marker genes and promotes triglyceride accumulation during 3T3-L1 differentiation. These results suggest that ERR{alpha} may play a critical role in adipocyte differentiation by modulating the expression of various adipogenesis-related genes.« less

Retinoid X receptor activation during adipogenesis of female mesenchymal stem cells programs a dysfunctional adipocyte.

PubMed

Shoucri, Bassem M; Hung, Victor T; Chamorro-García, Raquel; Shioda, Toshi; Blumberg, Bruce

2018-05-31

Early life exposure to endocrine disrupting chemicals (EDCs) is an emerging risk factor for the development of obesity and diabetes later in life. We previously showed that prenatal exposure to the EDC tributyltin (TBT) results in increased adiposity in the offspring. These effects linger into adulthood and are propagated through successive generations. TBT activates two nuclear receptors, the peroxisome proliferator-activated receptor γ (PPARγ) and its heterodimeric partner retinoid X receptor (RXR), that promote adipogenesis in vivo and in vitro. We recently employed a mesenchymal stem cell (MSC) model to show that TBT promotes adipose lineage commitment by activating RXR, not PPARγ. This led us to consider the functional consequences of PPARγ versus RXR activation in developing adipocytes. We used a transcriptomal approach to characterize genome-wide differences in MSCs differentiated with the PPARγ agonist rosiglitazone (ROSI) or TBT. Pathway analysis suggested functional deficits in TBT-treated cells. We then compared adipocytes differentiated with ROSI, TBT, or a pure RXR agonist IRX4204 (4204). Our data show that RXR activators ('rexinoids', 4204 and TBT) attenuate glucose uptake, blunt expression of the anti-diabetic hormone adiponectin, and fail to down-regulate pro-inflammatory and pro-fibrotic transcripts as does ROSI. Finally, 4204 and TBT treatment results in an inability to induce markers of adipocyte browning, in part due to sustained interferon signaling. Taken together, these data implicate rexinoids in the development of dysfunctional white adipose tissue that could potentially exacerbate obesity and/or diabetes risk in vivo. These data warrant further screening and characterization of EDCs that activate RXR.

Inhibition of fatty acid biosynthesis prevents adipocyte lipotoxicity on human osteoblasts in vitro

PubMed Central

Elbaz, Alexandre; Wu, Xiying; Rivas, Daniel; Gimble, Jeffrey M; Duque, Gustavo

2010-01-01

Abstract Although increased bone marrow fat in age-related bone loss has been associated with lower trabecular mass, the underlying mechanism responsible remains unknown. We hypothesized that marrow adipocytes exert a lipotoxic effect on osteoblast function and survival through the reversible biosynthesis of fatty acids (FA) into the bone marrow microenvironment. We have used a two-chamber system to co-culture normal human osteoblasts (NHOst) with differentiating pre-adipocytes in the absence or presence of an inhibitor of FA synthase (cerulenin) and separated by an insert that allowed unidirectional trafficking of soluble factors only and prevented direct cell–cell contact. Supernatants were assayed for the presence of FA using mass spectophotometry. After 3 weeks in co-culture, NHOst showed significantly lower levels of differentiation and function based on lower mineralization and expression of alkaline phosphatase, osterix, osteocalcin and Runx2. In addition, NHOst survival was affected by the presence of adipocytes as determined by MTS-formazan and TUNEL assays as well as higher activation of caspases 3/7. These toxic effects were inhibited by addition of cerulenin. Furthermore, culture of NHOst with either adipocyte-conditioned media alone in the absence of adipocytes themselves or with the addition of the most predominant FA (stearate or palmitate) produced similar toxic results. Finally, Runx2 nuclear binding was affected by addition of either adipocyte conditioned media or FA into the osteogenic media. We conclude that the presence of FA within the marrow milieu can contribute to the age-related changes in bone mass and can be prevented by the inhibition of FA synthase. PMID:19382912

Retinoic acid has different effects on UCP1 expression in mouse and human adipocytes

PubMed Central

2013-01-01

Background Increased adipose thermogenesis is being considered as a strategy aimed at preventing or reversing obesity. Thus, regulation of the uncoupling protein 1 (UCP1) gene in human adipocytes is of significant interest. Retinoic acid (RA), the carboxylic acid form of vitamin A, displays agonist activity toward several nuclear hormone receptors, including RA receptors (RARs) and peroxisome proliferator-activated receptor δ (PPARδ). Moreover, RA is a potent positive regulator of UCP1 expression in mouse adipocytes. Results The effects of all-trans RA (ATRA) on UCP1 gene expression in models of mouse and human adipocyte differentiation were investigated. ATRA induced UCP1 expression in all mouse white and brown adipocytes, but inhibited or had no effect on UCP1 expression in human adipocyte cell lines and primary human white adipocytes. Experiments with various RAR agonists and a RAR antagonist in mouse cells demonstrated that the stimulatory effect of ATRA on UCP1 gene expression was indeed mediated by RARs. Consistently, a PPARδ agonist was without effect. Moreover, the ATRA-mediated induction of UCP1 expression in mouse adipocytes was independent of PPARγ coactivator-1α. Conclusions UCP1 expression is differently affected by ATRA in mouse and human adipocytes. ATRA induces UCP1 expression in mouse adipocytes through activation of RARs, whereas expression of UCP1 in human adipocytes is not increased by exposure to ATRA. PMID:24059847

Nuclear factor I-C reciprocally regulates adipocyte and osteoblast differentiation via control of canonical Wnt signaling.

PubMed

Zhou, Jie; Wang, Shan; Qi, Qi; Yang, Xiaoyue; Zhu, Endong; Yuan, Hairui; Li, Xuemei; Liu, Ying; Li, Xiaoxia; Wang, Baoli

2017-05-01

Nuclear factor I-C (NFIC) has recently been identified as an important player in osteogenesis and bone homeostasis in vivo However, the molecular mechanisms involved have yet to be defined. In the current study, Nfic expression was altered in primary marrow stromal cells and established progenitor lines after adipogenic and osteogenic treatment. Overexpression of Nfic in stromal cells ST2, mesenchymal cells C3H10T1/2, and primary marrow stromal cells inhibited adipogenic differentiation, whereas it promoted osteogenic differentiation. Conversely, silencing of endogenous Nfic in the cell lines enhanced adipogenic differentiation, whereas it blocked osteogenic differentiation. Mechanism investigations revealed that Nfic overexpression promoted nuclear translocation of β-catenin and increased nuclear protein levels of β-catenin and transcription factor 7-like 2 (TCF7L2). Promoter studies and the chromatin immunoprecipitation (ChIP) assay revealed that NFIC directly binds to the promoter of low-density lipoprotein receptor-related protein 5 (Lrp5) and thereafter transactivates the promoter. Finally, inactivation of canonical Wnt signaling in ST2 attenuated the inhibition of adipogenic differentiation and stimulation of osteogenic differentiation by NFIC. Our study suggests that NFIC balances adipogenic and osteogenic differentiation from progenitor cells through controlling canonical Wnt signaling and highlights the potential of NFIC as a target for new therapies to control metabolic disorders like osteoporosis and obesity.-Zhou, J., Wang, S., Qi, Q., Yang, X., Zhu, E., Yuan, H., Li, X., Liu, Y., Li, X., Wang, B. Nuclear factor I-C reciprocally regulates adipocyte and osteoblast differentiation via control of canonical Wnt signaling. © FASEB.

Low ambient temperature during early postnatal development fails to cause a permanent induction of brown adipocytes

PubMed Central

Chabowska-Kita, Agnieszka; Trabczynska, Anna; Korytko, Agnieszka; Kaczmarek, Monika M.; Kozak, Leslie P.

2015-01-01

The brown adipocyte phenotype (BAP) in white adipose tissue (WAT) is transiently induced in adult mammals in response to reduced ambient temperature. Since it is unknown whether a cold challenge can permanently induce brown adipocytes (BAs), we reared C57BL/6J (B6) and AxB8/PgJ (AxB8) mice at 17 or 29°C from birth to weaning, to assess the BAP in young and adult mice. Energy balance measurements showed that 17°C reduced fat mass in the preweaning mice by increasing energy expenditure and suppressed diet-induced obesity in adults. Microarray analysis of global gene expression of inguinal fat (ING) from 10-day-old (D) mice indicates that expression at 17°C vs. 29°C was not different. Between 10 and 21 days of age, the BAP was induced coincident with morphologic remodeling of ING and marked changes in expression of neural development genes (e.g., Akap 12 and Ngfr). Analyses of Ucp1 mRNA and protein showed that 17°C transiently increased the BAP in ING from 21D mice; however, BAs were unexpectedly present in mice reared at 29°C. The involution of the BAP in WAT occurred after weaning in mice reared at 23°C. Therefore, the capacity to stimulate thermogenically competent BAs in WAT is set by a temperature-independent, genetically controlled program between birth and weaning.—Chabowska-Kita, A., Trabczynska, A., Korytko, A., Kaczmarek, M. M., Kozak, L. P. Low ambient temperature during early postnatal development fails to cause a permanent induction of brown adipocytes. PMID:25896784

Modulation of adipocyte biology by δ(9)-tetrahydrocannabinol.

PubMed

Teixeira, Diana; Pestana, Diogo; Faria, Ana; Calhau, Conceição; Azevedo, Isabel; Monteiro, Rosário

2010-11-01

It is recognized that the endocannabinoid system (ECS) plays a crucial role in the modulation of food intake and other aspects of energy metabolism. In this study, we aimed to investigate the effects of Δ(9)-tetrahydrocannabinol (THC) on adipocyte biology. 3T3-L1 cells were used to evaluate proliferation by sulforhodamine B (SRB) staining and methyl-(3)H-thymidine incorporation after 48 or 72 h of treatment with THC (1-500 nmol/l). Cells were differentiated in the presence or absence of the cannabinoid, and adipogenesis was determined by measuring lipid accumulation and peroxisome proliferator-activated receptor γ (PPARγ) transcription through reverse transcriptase-PCR (RT-PCR). Lipolysis was quantified under basal conditions or after isoproterenol (IP, 100 nmol/l) or insulin (INS, 100 nmol/l) treatment. Transforming growth factor β (TGFβ), diacylglycerol lipase α, and N-acylphosphatidylethanolamine-specific phospholipase D (NAPE-PLD) transcriptions were determined by RT-PCR in preadipocytes and adipocytes and adiponectin only in adipocytes. THC treatment increased culture protein content and reduced methyl-(3)H-thymidine incorporation. Cells treated with THC underwent adipogenesis shown by the expression of PPARγ and had increased lipid accumulation. Basal and IP-stimulated lipolyses were inhibited by THC and there was no effect on lipolysis of INS-treated adipocytes. The effects on methyl-(3)H-thymidine incorporation and lipolysis seem to be mediated through CB1- and CB2-dependent pathways. THC decreased NAPE-PLD in preadipocytes and increased adiponectin and TGFβ transcription in adipocytes. These results show that the ECS interferes with adipocyte biology and may contribute to adipose tissue (AT) remodeling. Although these observations point toward increased AT deposition, the stimulation of adiponectin production and inhibition of lipolysis may be in favor of improved INS sensitivity under cannabinoid influence.

The influence of mechanical stretching on mitosis, growth, and adipose conversion in adipocyte cultures.

PubMed

Shoham, Naama; Gefen, Amit

2012-09-01

The mechanotransduction of adipocytes is not well characterized in the literature. In this study, we employ stochastic modeling fitted to experiments for characterizing the influence of mechanical stretching delivered to adipocyte monolayers on the probabilities of commitment to the adipocyte lineage, mitosis, and growth after mitosis in 3T3-L1 adipocytes. We found that the probability of a cell to become committed to the adipocyte lineage in a single division when cultured on an elastic substrate was 0.025, which was indistinguishable between cultures that were radially stretched (to 12% strain) and control cultures. The probability of undergoing mitosis however was different between the groups, being 0.4 in the stretched cultures and 0.6 in the controls. The probability of growing after mitosis was affected by the stretching as well and was 0.9 and 0.8 in the stretched and control groups, respectively. We conclude that static stretching of the substrate of adipocyte cultures influences the mitotic potential of the cells as well as the growth potential post-mitosis. The present work provides better understanding of the mechanotransduction of adipocytes and in particular quantify how stretching influences the likelihood of cell proliferation and differentiation and, consequently, adipogenesis in the adipocyte cultures.

Adipocyte-derived Exosomal miRNAs: A Novel Mechanism for Obesity-Related Disease

PubMed Central

Ferrante, Sarah C; Nadler, Evan P; Pillai, Dinesh K; Hubal, Monica J; Wang, Zuyi; Wang, Justin M; Gordish-Dressman, Heather; Koeck, Emily; Sevilla, Samantha; Wiles, Andrew A; Freishtat, Robert J

2014-01-01

Background Obesity is frequently complicated by comorbid conditions, yet how excess adipose contributes is poorly understood. Although adipocytes in obese individuals induce systemic inflammation via secreted cytokines, another potential mediator has recently been identified (i.e. adipocyte-derived exosomes). We hypothesized that adipocyte-derived exosomes contain mediators capable of activating end-organ inflammatory and fibrotic signaling pathways. Methods We developed techniques to quantify and characterize exosomes shed by adipocytes from 7 obese (age: 12–17.5 years, BMI: 33–50 kg/m2) and 5 lean (age: 11–19 years, BMI: 22–25 kg/m2) subjects. Results Abundant exosomal miRNAs, but no mRNAs, were detected. Comparison of obese vs. lean visceral adipose donors detected 55 differentially-expressed miRNAs (p<0.05; fold change≥|1.2|). qRT-PCR confirmed downregulation of miR-148b (ratio = 0.2 [95% confidence interval = 0.1, 0.6]) and miR-4269 (0.3 [0.1, 0.8]), and upregulation of miR-23b (6.2 [2.2, 17.8]) and miR-4429 (3.8 [1.1 to 13.4]). Pathways analysis identified TGF-β signaling and Wnt/ β-catenin signaling among the top canonical pathways expected to be altered with visceral adiposity based on projected mRNA targets for the 55 differentially expressed miRNAs. A select mRNA target was validated in vitro. Conclusion These data show that visceral adipocytes shed exosomal-mediators predicted to regulate key end-organ inflammatory and fibrotic signaling pathways. PMID:25518011

Atypical antipsychotics induce both proinflammatory and adipogenic gene expression in human adipocytes in vitro.

PubMed

Sárvári, Anitta K; Veréb, Zoltán; Uray, Iván P; Fésüs, László; Balajthy, Zoltán

2014-08-08

Schizophrenia requires lifelong treatment, potentially causing systemic changes in metabolic homeostasis. In the clinical setting, antipsychotic treatment may differentially lead to weight gain among individual patients, although the molecular determinants of such adverse effects are currently unknown. In this study, we investigated changes in the expression levels of critical regulatory genes of adipogenesis, lipid metabolism and proinflammatory genes during the differentiation of primary human adipose-derived stem cells (ADSCs). These cells were isolated from patients with body mass indices <25 and treated with the second-generation antipsychotics olanzapine, ziprasidone, clozapine, quetiapine, aripiprazole and risperidone and the first-generation antipsychotic haloperidol. We found that antipsychotics exhibited a marked effect on key genes involved in the regulation of cell cycle, signal transduction, transcription factors, nuclear receptors, differentiation markers and metabolic enzymes. In particular, we observed an induction of the transcription factor NF-KB1 and NF-KB1 target genes in adipocytes in response to these drugs, including the proinflammatory cytokines TNF-α, IL-1β, IL-8 and MCP-1. In addition, enhanced secretion of both IL8 and MCP-1 was observed in the supernatant of these cell cultures. In addition to their remarkable stimulatory effects on proinflammatory gene transcription, three of the most frequently prescribed antipsychotic drugs, clozapine, quetiapine and aripiprazole, also induced the expression of essential adipocyte differentiation genes and the adipocyte hormones leptin and adiponectin, suggesting that both glucose and fat metabolism may be affected by these drugs. These data further suggest that antipsychotic treatments in patients alter the gene expression patterns in adipocytes in a coordinated fashion and priming them for a low-level inflammatory state. Copyright © 2014 Elsevier Inc. All rights reserved.

Protein Kinase Inhibitor γ reciprocally regulates osteoblast and adipocyte differentiation by downregulating Leukemia Inhibitory Factor

PubMed Central

Chen, Xin; Hausman, Bryan S.; Luo, Guangbin; Zhou, Guang; Murakami, Shunichi; Rubin, Janet; Greenfield, Edward M.

2013-01-01

The Protein Kinase Inhibitor (Pki) gene family inactivates nuclear PKA and terminates PKA-induced gene expression. We previously showed that Pkig is the primary family member expressed in osteoblasts and that Pkig knockdown increases the effects of parathyroid hormone and isoproterenol on PKA activation, gene expression, and inhibition of apoptosis. Here, we determined whether endogenous levels of Pkig regulate osteoblast differentiation. Pkig is the primary family member in MEFs, murine marrow-derived mesenchymal stem cells, and human mesenchymal stem cells. Pkig deletion increased forskolin-dependent nuclear PKA activation and gene expression and Pkig deletion or knockdown increased osteoblast differentiation. PKA signaling is known to stimulate adipogenesis; however, adipogenesis and osteogenesis are often reciprocally regulated. We found that the reciprocal regulation predominates over the direct effects of PKA since adipogenesis was decreased by Pkig deletion or knockdown. Pkig deletion or knockdown simultaneously increased osteogenesis and decreased adipogenesis in mixed osteogenic/adipogenic medium. Pkig deletion increased PKA-induced expression of Leukemia Inhibitory Factor (Lif) mRNA and LIF protein. LIF neutralizing antibodies inhibited the effects on osteogenesis and adipogenesis of either Pkig deletion in MEFs or PKIγ knockdown in both murine and human mesenchymal stem cells. Collectively, our results show that endogenous levels of Pkig reciprocally regulate osteoblast and adipocyte differentiation and that this reciprocal regulation is mediated in part by LIF. PMID:23963683

Adipocytes activate mitochondrial fatty acid oxidation and autophagy to promote tumor growth in colon cancer.

PubMed

Wen, Yang-An; Xing, Xiaopeng; Harris, Jennifer W; Zaytseva, Yekaterina Y; Mitov, Mihail I; Napier, Dana L; Weiss, Heidi L; Mark Evers, B; Gao, Tianyan

2017-02-02

Obesity has been associated with increased incidence and mortality of a wide variety of human cancers including colorectal cancer. However, the molecular mechanism by which adipocytes regulate the metabolism of colon cancer cells remains elusive. In this study, we showed that adipocytes isolated from adipose tissues of colon cancer patients have an important role in modulating cellular metabolism to support tumor growth and survival. Abundant adipocytes were found in close association with invasive tumor cells in colon cancer patients. Co-culture of adipocytes with colon cancer cells led to a transfer of free fatty acids that released from the adipocytes to the cancer cells. Uptake of fatty acids allowed the cancer cells to survive nutrient deprivation conditions by upregulating mitochondrial fatty acid β-oxidation. Mechanistically, co-culture of adipocytes or treating cells with fatty acids induced autophagy in colon cancer cells as a result of AMPK activation. Inhibition of autophagy attenuated the ability of cancer cells to utilize fatty acids and blocked the growth-promoting effect of adipocytes. In addition, we found that adipocytes stimulated the expression of genes associated with cancer stem cells and downregulated genes associated with intestinal epithelial cell differentiation in primary colon cancer cells and mouse tumor organoids. Importantly, the presence of adipocytes promoted the growth of xenograft tumors in vivo. Taken together, our results show that adipocytes in the tumor microenvironment serve as an energy provider and a metabolic regulator to promote the growth and survival of colon cancer cells.

Adipocytes activate mitochondrial fatty acid oxidation and autophagy to promote tumor growth in colon cancer

PubMed Central

Wen, Yang-An; Xing, Xiaopeng; Harris, Jennifer W; Zaytseva, Yekaterina Y; Mitov, Mihail I; Napier, Dana L; Weiss, Heidi L; Mark Evers, B; Gao, Tianyan

2017-01-01

Obesity has been associated with increased incidence and mortality of a wide variety of human cancers including colorectal cancer. However, the molecular mechanism by which adipocytes regulate the metabolism of colon cancer cells remains elusive. In this study, we showed that adipocytes isolated from adipose tissues of colon cancer patients have an important role in modulating cellular metabolism to support tumor growth and survival. Abundant adipocytes were found in close association with invasive tumor cells in colon cancer patients. Co-culture of adipocytes with colon cancer cells led to a transfer of free fatty acids that released from the adipocytes to the cancer cells. Uptake of fatty acids allowed the cancer cells to survive nutrient deprivation conditions by upregulating mitochondrial fatty acid β-oxidation. Mechanistically, co-culture of adipocytes or treating cells with fatty acids induced autophagy in colon cancer cells as a result of AMPK activation. Inhibition of autophagy attenuated the ability of cancer cells to utilize fatty acids and blocked the growth-promoting effect of adipocytes. In addition, we found that adipocytes stimulated the expression of genes associated with cancer stem cells and downregulated genes associated with intestinal epithelial cell differentiation in primary colon cancer cells and mouse tumor organoids. Importantly, the presence of adipocytes promoted the growth of xenograft tumors in vivo. Taken together, our results show that adipocytes in the tumor microenvironment serve as an energy provider and a metabolic regulator to promote the growth and survival of colon cancer cells. PMID:28151470

Phytol stimulates the browning of white adipocytes through the activation of AMP-activated protein kinase (AMPK) α in mice fed high-fat diet.

PubMed

Zhang, Fenglin; Ai, Wei; Hu, Xiaoquan; Meng, Yingying; Yuan, Cong; Su, Han; Wang, Lina; Zhu, Xiaotong; Gao, Ping; Shu, Gang; Jiang, Qingyan; Wang, Songbo

2018-04-25

Stimulating the browning of white adipocytes contributes to the restriction of obesity and related metabolic disorders. This study aimed to investigate the browning effects of phytol on mice inguinal subcutaneous white adipose tissue (iWAT) and explore the underlying mechanisms. Our results demonstrated that phytol administration decreased body weight gain and iWAT index, and stimulated the browning of mice iWAT, with the increased expression of brown adipocyte marker genes (UCP1, PRDM16, PGC1α, PDH, and Cyto C). In addition, phytol treatment activated the AMPKα signaling pathway in mice iWAT. In good agreement with the in vivo findings, the in vitro results showed that 100 μM phytol stimulated brown adipogenic differentiation and formation of brown-like adipocytes in the differentiated 3T3-L1 by increasing the mitochondria content and oxygen consumption, and promoting mRNA and/or protein expression of brown adipocyte markers (UCP1, PRDM16, PGC1α, PDH, Cyto C, Cidea and Elovl3) and beige adipocyte markers (CD137 and TMEM26). Meanwhile, phytol activated the AMPKα signaling pathway in the differentiated 3T3-L1. However, the inhibition of AMPKα with Compound C totally abolished phytol-stimulated brown adipogenic differentiation and formation of brown-like adipocytes. In conclusion, these results showed that phytol stimulated the browning of mice iWAT, which was coincident with the increased formation of brown-like adipocytes in the differentiated 3T3-L1, and appeared to be primarily mediated by the AMPKα signaling pathway. These data provided new insight into the role of phytol in regulating the browning of WAT and suggested the potential application of phytol as a nutritional intervention for the restriction of obesity and related metabolic disorders.

Endoplasmic reticulum stress suppresses lipin-1 expression in 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Nobuhiko, E-mail: ntkhs@hoku-iryo-u.ac.jp; Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1, Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510; Yoshizaki, Takayuki

Highlights: ► Lipin-1 involves lipid metabolism, adipocyte differentiation, and inflammation. ► Adipose lipin-1 expression is reduced in obesity. ► ER stress suppresses lipin-1 expression in 3T3-L1 adipocytes. ► Activation of PPAR-γ recovers ER stress-induced lipin-1 reduction. -- Abstract: Lipin-1 plays crucial roles in the regulation of lipid metabolism and cell differentiation in adipocytes. In obesity, adipose lipin-1 mRNA expression is decreased and positively correlated with systemic insulin sensitivity. Amelioration of the lipin-1 depletion might be improved dysmetabolism. Although some cytokines such as TNF-α and interleukin-1β reduces adipose lipin-1 expression, the mechanism of decreased adipose lipin-1 expression in obesity remains unclear.more » Recently, endoplasmic reticulum (ER) stress is implicated in the pathogenesis of obesity. Here we investigated the role of ER stress on the lipin-1 expression in 3T3-L1 adipocytes. We demonstrated that lipin-1 expression was suppressed by the treatment with ER stress inducers (tunicamycin and thapsigargin) at transcriptional level. We also showed that constitutive lipin-1 expression could be maintained by peroxisome proliferator-activated receptor-γ in 3T3-L1 adipocytes. Activation of peroxisome proliferator-activated receptor-γ recovered the ER stress-induced lipin-1 suppression. These results suggested that ER stress might be involved in the pathogenesis of obesity through lipin-1 depletion.« less

6-gingerol inhibits rosiglitazone-induced adipogenesis in 3T3-L1 adipocytes.

PubMed

Tzeng, Thing-Fong; Chang, Chia Ju; Liu, I-Min

2014-02-01

We investigated the effects of 6-gingerol ((S)-5-hydroxy-1-(4-hydroxy-3-methoxyphenyl)-3-decanone) on the inhibition of rosiglitazone (RGZ)-induced adipogenesis in 3T3-L1 cells. The morphological changes were photographed based on staining lipid accumulation by Oil-Red O in RGZ (1 µmol/l)-treated 3T3-L1 cells without or with various concentrations of 6-gingerol on differentiation day 8. Quantitation of triglycerides content was performed in cells on day 8 after differentiation induction. Differentiated cells were lysed to detect mRNA and protein levels of adipocyte-specific transcription factors by real-time reverse transcription-polymerase chain reaction and Western blot analysis, respectively. 6-gingerol (50 µmol/l) effectively suppressed oil droplet accumulation and reduced the sizes of the droplets in RGZ-induced adipocyte differentiation in 3T3-L1 cells. The triglyceride accumulation induced by RGZ in differentiated 3T3-L1 cells was also reduced by 6-gingerol (50 µmol/l). Treatment of differentiated 3T3-L1 cells with 6-gingerol (50 µmol/l) antagonized RGZ-induced gene expression of peroxisome proliferator-activated receptor (PPAR)γ and CCAAT/enhancer-binding protein α. Additionally, the increased levels of mRNA and protein in adipocyte-specific fatty acid binding protein 4 and fatty acid synthase induced by RGZ in 3T3-L1 cells were decreased upon treatment with 6-gingerol. Our data suggests that 6-gingerol may be beneficial in obesity, by reducing adipogenesis partly through the down-regulating PPARγ activity. Copyright © 2013 John Wiley & Sons, Ltd.

Adipocyte Metabolic Pathways Regulated by Diet Control the Female Germline Stem Cell Lineage in Drosophila melanogaster

PubMed Central

Matsuoka, Shinya; Armstrong, Alissa R.; Sampson, Leesa L.; Laws, Kaitlin M.; Drummond-Barbosa, Daniela

2017-01-01

Nutrients affect adult stem cells through complex mechanisms involving multiple organs. Adipocytes are highly sensitive to diet and have key metabolic roles, and obesity increases the risk for many cancers. How diet-regulated adipocyte metabolic pathways influence normal stem cell lineages, however, remains unclear. Drosophila melanogaster has highly conserved adipocyte metabolism and a well-characterized female germline stem cell (GSC) lineage response to diet. Here, we conducted an isobaric tags for relative and absolute quantification (iTRAQ) proteomic analysis to identify diet-regulated adipocyte metabolic pathways that control the female GSC lineage. On a rich (relative to poor) diet, adipocyte Hexokinase-C and metabolic enzymes involved in pyruvate/acetyl-CoA production are upregulated, promoting a shift of glucose metabolism toward macromolecule biosynthesis. Adipocyte-specific knockdown shows that these enzymes support early GSC progeny survival. Further, enzymes catalyzing fatty acid oxidation and phosphatidylethanolamine synthesis in adipocytes promote GSC maintenance, whereas lipid and iron transport from adipocytes controls vitellogenesis and GSC number, respectively. These results show a functional relationship between specific metabolic pathways in adipocytes and distinct processes in the GSC lineage, suggesting the adipocyte metabolism–stem cell link as an important area of investigation in other stem cell systems. PMID:28396508

Adipocyte Metabolic Pathways Regulated by Diet Control the Female Germline Stem Cell Lineage in Drosophila melanogaster.

PubMed

Matsuoka, Shinya; Armstrong, Alissa R; Sampson, Leesa L; Laws, Kaitlin M; Drummond-Barbosa, Daniela

2017-06-01

Nutrients affect adult stem cells through complex mechanisms involving multiple organs. Adipocytes are highly sensitive to diet and have key metabolic roles, and obesity increases the risk for many cancers. How diet-regulated adipocyte metabolic pathways influence normal stem cell lineages, however, remains unclear. Drosophila melanogaster has highly conserved adipocyte metabolism and a well-characterized female germline stem cell (GSC) lineage response to diet. Here, we conducted an isobaric tags for relative and absolute quantification (iTRAQ) proteomic analysis to identify diet-regulated adipocyte metabolic pathways that control the female GSC lineage. On a rich (relative to poor) diet, adipocyte Hexokinase-C and metabolic enzymes involved in pyruvate/acetyl-CoA production are upregulated, promoting a shift of glucose metabolism toward macromolecule biosynthesis. Adipocyte-specific knockdown shows that these enzymes support early GSC progeny survival. Further, enzymes catalyzing fatty acid oxidation and phosphatidylethanolamine synthesis in adipocytes promote GSC maintenance, whereas lipid and iron transport from adipocytes controls vitellogenesis and GSC number, respectively. These results show a functional relationship between specific metabolic pathways in adipocytes and distinct processes in the GSC lineage, suggesting the adipocyte metabolism-stem cell link as an important area of investigation in other stem cell systems. Copyright © 2017 by the Genetics Society of America.

Monoethylhexyl Phthalate Elicits an Inflammatory Response in Adipocytes Characterized by Alterations in Lipid and Cytokine Pathways.

PubMed

Manteiga, Sara; Lee, Kyongbum

2017-04-01

A growing body of evidence links endocrine-disrupting chemicals (EDCs) with obesity-related metabolic diseases. While it has been shown that EDCs can predispose individuals toward adiposity by affecting developmental processes, little is known about the chemicals' effects on adult adipose tissue. Our aim was to study the effects of low, physiologically relevant doses of EDCs on differentiated murine adipocytes. We combined metabolomics, proteomics, and gene expression analysis to characterize the effects of mono-ethylhexyl phthalate (MEHP) in differentiated adipocytes. Repeated exposure to MEHP over several days led to changes in metabolite and enzyme levels indicating elevated lipogenesis and lipid oxidation. The chemical exposure also increased expression of major inflammatory cytokines, including chemotactic factors. Proteomic and gene expression analysis revealed significant alterations in pathways regulated by peroxisome proliferator activated receptor-γ (PPARγ). Inhibiting the nuclear receptor's activity using a chemical antagonist abrogated not only the alterations in PPARγ-regulated metabolic pathways, but also the increases in cytokine expression. Our results show that MEHP can induce a pro-inflammatory state in differentiated adipocytes. This effect is at least partially mediated PPARγ.

Monoethylhexyl Phthalate Elicits an Inflammatory Response in Adipocytes Characterized by Alterations in Lipid and Cytokine Pathways

PubMed Central

Manteiga, Sara; Lee, Kyongbum

2016-01-01

Background: A growing body of evidence links endocrine-disrupting chemicals (EDCs) with obesity-related metabolic diseases. While it has been shown that EDCs can predispose individuals toward adiposity by affecting developmental processes, little is known about the chemicals’ effects on adult adipose tissue. Objectives: Our aim was to study the effects of low, physiologically relevant doses of EDCs on differentiated murine adipocytes. Methods: We combined metabolomics, proteomics, and gene expression analysis to characterize the effects of mono-ethylhexyl phthalate (MEHP) in differentiated adipocytes. Results: Repeated exposure to MEHP over several days led to changes in metabolite and enzyme levels indicating elevated lipogenesis and lipid oxidation. The chemical exposure also increased expression of major inflammatory cytokines, including chemotactic factors. Proteomic and gene expression analysis revealed significant alterations in pathways regulated by peroxisome proliferator activated receptor-γ (PPARγ). Inhibiting the nuclear receptor’s activity using a chemical antagonist abrogated not only the alterations in PPARγ-regulated metabolic pathways, but also the increases in cytokine expression. Conclusions: Our results show that MEHP can induce a pro-inflammatory state in differentiated adipocytes. This effect is at least partially mediated PPARγ. Citation: Manteiga S, Lee K. 2017. Monoethylhexyl phthalate elicits an inflammatory response in adipocytes characterized by alterations in lipid and cytokine pathways. Environ Health Perspect 125:615–622; http://dx.doi.org/10.1289/EHP464 PMID:27384973

Irisin exerts dual effects on browning and adipogenesis of human white adipocytes.

PubMed

Zhang, Yuan; Xie, Chao; Wang, Hai; Foss, Robin M; Clare, Morgan; George, Eva Vertes; Li, Shiwu; Katz, Adam; Cheng, Henrique; Ding, Yousong; Tang, Dongqi; Reeves, Westley H; Yang, Li-Jun

2016-08-01

To better understand the role of irisin in humans, we examined the effects of irisin in human primary adipocytes and fresh human subcutaneous white adipose tissue (scWAT). Human primary adipocytes derived from 28 female donors' fresh scWAT were used to examine the effects of irisin on browning and mitochondrial respiration, and preadipocytes were used to examine the effects of irisin on adipogenesis and osteogenesis. Cultured fragments of scWAT and perirenal brown fat were used for investigating signal transduction pathways that mediate irisin's browning effect by Western blotting to detect phosphorylated forms of p38, ERK, and STAT3 as well as uncoupling protein 1 (UCP1). Individual responses to irisin in scWAT were correlated with basal expression levels of brown/beige genes. Irisin upregulated the expression of browning-associated genes and UCP1 protein in both cultured primary mature adipocytes and fresh adipose tissues. It also significantly increased thermogenesis at 5 nmol/l by elevating cellular energy metabolism (OCR and ECAR). Treating human scWAT with irisin increased UCP1 expression by activating the ERK and p38 MAPK signaling. Blocking either pathway with specific inhibitors abolished irisin-induced UCP1 upregulation. However, our results showed that UCP1 in human perirenal adipose tissue was insensitive to irisin. Basal levels of brown/beige and FNDC5 genes correlated positively with the browning response of scWAT to irisin. In addition, irisin significantly inhibited adipogenic differentiation but promoted osteogenic differentiation. We conclude that irisin promotes "browning" of mature white adipocytes by increasing cellular thermogenesis, whereas it inhibits adipogenesis and promotes osteogenesis during lineage-specific differentiation. Our findings provide a rationale for further exploring the therapeutic use of irisin in obesity and exercise-associated bone formation.

Adipogenesis-related increase of semicarbazide-sensitive amine oxidase and monoamine oxidase in human adipocytes.

PubMed

Bour, Sandy; Daviaud, Danièle; Gres, Sandra; Lefort, Corinne; Prévot, Danielle; Zorzano, Antonio; Wabitsch, Martin; Saulnier-Blache, Jean-Sébastien; Valet, Philippe; Carpéné, Christian

2007-08-01

A strong induction of semicarbazide-sensitive amine oxidase (SSAO) has previously been reported during murine preadipocyte lineage differentiation but it remains unknown whether this emergence also occurs during adipogenesis in man. Our aim was to compare SSAO and monoamine oxidase (MAO) expression during in vitro differentiation of human preadipocytes and in adipose and stroma-vascular fractions of human fat depots. A human preadipocyte cell strain from a patient with Simpson-Golabi-Behmel syndrome was first used to follow amine oxidase expression during in vitro differentiation. Then, human preadipocytes isolated from subcutaneous adipose tissues were cultured under conditions promoting ex vivo adipose differentiation and tested for MAO and SSAO expression. Lastly, human adipose tissue was separated into mature adipocyte and stroma-vascular fractions for analyses of MAO and SSAO at mRNA, protein and activity levels. Both SSAO and MAO were increased from undifferentiated preadipocytes to lipid-laden cells in all the models: 3T3-F442A and 3T3-L1 murine lineages, human SGBS cell strain or human preadipocytes in primary culture. In human subcutaneous adipose tissue, the adipocyte-enriched fraction exhibited seven-fold higher amine oxidase activity and contained three- to seven-fold higher levels of mRNAs encoded by MAO-A, MAO-B, AOC3 and AOC2 genes than the stroma-vascular fraction. MAO-A and AOC3 genes accounted for the majority of their respective MAO and SSAO activities in human adipose tissue. Most of the SSAO and MAO found in adipose tissue originated from mature adipocytes. Although the mechanism and role of adipogenesis-related increase in amine oxidase expression remain to be established, the resulting elevated levels of amine oxidase activities found in human adipocytes may be of potential interest for therapeutic intervention in obesity.

Adipocyte triglyceride turnover and lipolysis in lean and overweight subjects.

PubMed

Rydén, Mikael; Andersson, Daniel P; Bernard, Samuel; Spalding, Kirsty; Arner, Peter

2013-10-01

Human obesity is associated with decreased triglyceride turnover and impaired lipolysis in adipocytes. We determined whether such defects also occur in subjects with only moderate increase in fat mass. Human abdominal subcutaneous adipose tissue was investigated in healthy, nonobese subjects [body mass index (BMI) > 17 kg/m(2) and BMI < 30 kg/m(2)]. Triglyceride age, reflecting lipid turnover, was examined in 41 subjects by assessing the incorporation of atmospheric (14)C into adipose lipids. Adipocyte lipolysis was examined as the ability of lipolytic agents to stimulate glycerol release in 333 subjects. Adipocyte triglyceride age was markedly increased in overweight (BMI ≥ 25 kg/m(2)) compared with lean subjects (P = 0.017) with triglyceride T1/2 of 14 and 9 months, respectively (P = 0.04). Triglyceride age correlated positively with BMI (P = 0.002) but not with adipocyte volume (P = 0.2). Noradrenaline-, isoprenaline- or dibutyryl cyclic AMP-induced lipolysis was inversely correlated with triglyceride age (P < 0.01) and BMI (P < 0.0001) independently of basal lipolysis, gender, and nicotine use. Current, but not the highest or lowest BMI in adult life, correlated significantly (inversely) with lipolysis. In conclusion, adipocyte triglyceride turnover and lipolytic activity are decreased in overweight subjects and reflect the current BMI status. These changes may confer an increased risk for early development and/or maintenance of excess body fat.

Activation of IRF1 in Human Adipocytes Leads to Phenotypes Associated with Metabolic Disease.

PubMed

Friesen, Max; Camahort, Raymond; Lee, Youn-Kyoung; Xia, Fang; Gerszten, Robert E; Rhee, Eugene P; Deo, Rahul C; Cowan, Chad A

2017-05-09

The striking rise of obesity-related metabolic disorders has focused attention on adipocytes as critical mediators of disease phenotypes. To better understand the role played by excess adipose in metabolic dysfunction it is crucial to decipher the transcriptional underpinnings of the low-grade adipose inflammation characteristic of diseases such as type 2 diabetes. Through employing a comparative transcriptomics approach, we identified IRF1 as differentially regulated between primary and in vitro-derived genetically matched adipocytes. This suggests a role as a mediator of adipocyte inflammatory phenotypes, similar to its function in other tissues. Utilizing adipose-derived mesenchymal progenitors we subsequently demonstrated that expression of IRF1 in adipocytes indeed contributes to upregulation of inflammatory processes, both in vitro and in vivo. This highlights IRF1's relevance to obesity-related inflammation and the resultant metabolic dysregulation. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Featured Article: Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells

PubMed Central

Ezquer, Fernando; Espinosa, Maximiliano; Arango-Rodriguez, Martha; Puebla, Carlos; Sobrevia, Luis; Conget, Paulette

2015-01-01

The final product of adipogenesis is a functional adipocyte. This mature cell acquires the necessary machinery for lipid metabolism, loses its proliferation potential, increases its insulin sensitivity, and secretes adipokines. Multipotent mesechymal stromal cells have been recognized as a source of adipocytes both in vivo and in vitro. The in vitro adipogenic differentiation of human MSC (hMSC) has been induced up to now by using a complex stimulus which includes dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin (a classical cocktail) and evaluated according to morphological changes. The present work was aimed at demonstrating that the simultaneous activation of dexamethasone’s canonical signaling pathways, through the glucocorticoid receptor and CCAAT-enhancer-binding proteins (C/EBPs) and rosiglitazone through peroxisome proliferator-activated receptor gamma (PPAR-gamma) is sufficient yet necessary for inducing hMSC adipogenic differentiation. It was also ascertained that hMSC exposed just to dexamethasone and rosiglitazone (D&R) differentiated into cells which accumulated neutral lipid droplets, expressed C/EBP-alpha, PPAR-gamma, aP2, lipoprotein lipase, acyl-CoA synthetase, phosphoenolpyruvate carboxykinase, adiponectin, and leptin genes but did not proliferate. Glucose uptake was dose dependent on insulin stimulus and high levels of adipokines were secreted (i.e. displaying not only the morphology but also expressing mature adipocytes’ specific genes and functional characteristics). This work has demonstrated that (i) the activating C/EBPs and PPAR-gamma signaling pathways were sufficient to induce adipogenic differentiation from hMSC, (ii) D&R producing functional adipocytes from hMSC, (iii) D&R induce adipogenic differentiation from mammalian MSC (including those which are refractory to classical adipogenic differentiation stimuli). D&R would thus seem to be a useful tool for MSC characterization, studying adipogenesis pathways and

Unravelling hair follicle-adipocyte communication.

PubMed

Schmidt, Barbara; Horsley, Valerie

2012-11-01

Here, we explore the established and potential roles for intradermal adipose tissue in communication with hair follicle biology. The hair follicle delves deep into the rich dermal macroenvironment as it grows to maturity where it is surrounded by large lipid-filled adipocytes. Intradermal adipocytes regenerate with faster kinetics than other adipose tissue depots and in parallel with the hair cycle, suggesting an interplay exists between hair follicle cells and adipocytes. While adipocytes have well-established roles in metabolism and energy storage, until recently, they were overlooked as niche cells that provide important growth signals to neighbouring skin cells. We discuss recent data supporting adipocytes as niche cells for the skin and skin pathologies that may be related to alterations in skin adipose tissue defects. © 2012 John Wiley & Sons A/S.

Sida rhomboidea. Roxb leaf extract down-regulates expression of PPARγ2 and leptin genes in high fat diet fed C57BL/6J Mice and retards in vitro 3T3L1 pre-adipocyte differentiation.

PubMed

Thounaojam, Menaka C; Jadeja, Ravirajsinh N; Ramani, Umed V; Devkar, Ranjitsinh V; Ramachandran, A V

2011-01-01

Sida rhomboidea. Roxb leaf extract (SRLE) is being used by the populace of North-East India to alleviate symptoms of diabetes and obesity. We have previously reported its hypolipidemic and anti-diabetic properties. In this study, we report the effect of SRLE on (i) in vivo modulation of genes controlling high fat diet (HFD) induced obesity and (ii) in vitro 3T3L1 pre-adipocyte differentiation and leptin release. Supplementation with SRLE significantly prevented HFD induced increment in bodyweight, plasma lipids and leptin, visceral adiposity and adipocyte hypertrophy. Also, SRLE supplementation reduced food intake, down regulated PPARγ2, SREBP1c, FAS and LEP expressions and up-regulated CPT-1 in epididymal adipose tissue compared to obese mice. In vitro adipogenesis of 3T3L1 pre-adipocytes was significantly retarded in the presence of SRLE extract. Also decreased triglyceride accumulation, leptin release and glyceraldehyde-3-Phosphate dehydrogenase activity along with higher glycerol release without significant alteration of viability of 3T3L1 pre-adipocytes, was recorded. Our findings suggest that prevention of HFD induced visceral adiposity is primarily by down regulation of PPARγ2 and leptin gene expression coupled with attenuation of food intake in C57BL/6J mice. SRLE induced prevention of pre-adipocytes differentiation, and leptin release further substantiated these findings and scientifically validates the potential application of SRLE as a therapeutic agent against obesity.

Sida rhomboidea. Roxb Leaf Extract Down-Regulates Expression of PPARγ2 and Leptin Genes in High Fat Diet Fed C57BL/6J Mice and Retards in Vitro 3T3L1 Pre-Adipocyte Differentiation

PubMed Central

Thounaojam, Menaka C.; Jadeja, Ravirajsinh N.; Ramani, Umed V.; Devkar, Ranjitsinh V.; Ramachandran, A. V.

2011-01-01

Sida rhomboidea. Roxb leaf extract (SRLE) is being used by the populace of North-East India to alleviate symptoms of diabetes and obesity. We have previously reported its hypolipidemic and anti-diabetic properties. In this study, we report the effect of SRLE on (i) in vivo modulation of genes controlling high fat diet (HFD) induced obesity and (ii) in vitro 3T3L1 pre-adipocyte differentiation and leptin release. Supplementation with SRLE significantly prevented HFD induced increment in bodyweight, plasma lipids and leptin, visceral adiposity and adipocyte hypertrophy. Also, SRLE supplementation reduced food intake, down regulated PPARγ2, SREBP1c, FAS and LEP expressions and up-regulated CPT-1 in epididymal adipose tissue compared to obese mice. In vitro adipogenesis of 3T3L1 pre-adipocytes was significantly retarded in the presence of SRLE extract. Also decreased triglyceride accumulation, leptin release and glyceraldehyde-3-Phosphate dehydrogenase activity along with higher glycerol release without significant alteration of viability of 3T3L1 pre-adipocytes, was recorded. Our findings suggest that prevention of HFD induced visceral adiposity is primarily by down regulation of PPARγ2 and leptin gene expression coupled with attenuation of food intake in C57BL/6J mice. SRLE induced prevention of pre-adipocytes differentiation, and leptin release further substantiated these findings and scientifically validates the potential application of SRLE as a therapeutic agent against obesity. PMID:21845103

Green tea seed oil reduces weight gain in C57BL/6J mice and influences adipocyte differentiation by suppressing peroxisome proliferator-activated receptor-gamma.

PubMed

Kim, Na-Hyung; Choi, Sun-Kyung; Kim, Su-Jin; Moon, Phil-Dong; Lim, Hun-Sun; Choi, In-Young; Na, Ho-Jeong; An, Hyo-Jin; Myung, Noh-Yil; Jeong, Hyun-Ja; Um, Jae-Young; Hong, Seung-Heon; Kim, Hyung-Min

2008-11-01

Given that tea contains a number of chemical constituents possessing medicinal and pharmacological properties, green tea seed is also believed to contain many biologically active compounds such as saponin, flavonoids, vitamins, and oil materials. However, little is known about the physiologic functions of green tea seed oil. The aim of this study is to investigate the anti-obesity effects of green tea seed oil in C57BL/6J mice and in preadipocyte 3T3L-1 cell lines. In vivo, three groups of mice were fed with a standard diet, a high-fat diet containing 30% shortening, or 30% of green tea seed oil based on a standard diet for 85 days. The levels of total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglyceride, glucose, and alanine aminotransferase in blood were analyzed at the end of the study. The mice given green tea seed oil gained less weight compared to mice given the shortening diet (p < 0.01). The plasma level of total cholesterol was decreased by a significant level of 32.4% in mice given the green tea seed oil compared to the mice given the shortening diet (p < 0.01). In addition, 3T3-L1 cells were treated for 2 days to evaluate effects of green tea seed oil on adipocyte differentiation. Green tea seed oil inhibited expression of peroxisome proliferator-activated receptor-gamma(2) and CCAAT/enhancer binding protein-alpha in adipocytes and adipose tissue from the experimental animals. These results indicate that the anti-obesity effects of green tea seed oil might be, in part, through suppression of transcription factors related to adipocyte differentiation.

4E-BP1 regulates the differentiation of white adipose tissue.

PubMed

Tsukiyama-Kohara, Kyoko; Katsume, Asao; Kimura, Kazuhiro; Saito, Masayuki; Kohara, Michinori

2013-07-01

4E Binding protein 1 (4E-BP1) suppresses translation initiation. The absence of 4E-BP1 drastically reduces the amount of adipose tissue in mice. To address the role of 4E-BP1 in adipocyte differentiation, we characterized 4E-BP1(-/-) mice in this study. The lack of 4E-BP1 decreased the amount of white adipose tissue and increased the amount of brown adipose tissue. In 4E-BP1(-/-) MEF cells, PPARγ coactivator 1 alpha (PGC-1α) expression increased and exogenous 4E-BP1 expression suppressed PGC-1α expression. The level of 4E-BP1 expression was higher in white adipocytes than in brown adipocytes and showed significantly greater up-regulation in white adipocytes than in brown adipocytes during preadipocyte differentiation into mature adipocytes. The amount of PGC-1α was consistently higher in HB cells (a brown preadipocyte cell line) than in HW cells (a white preadipocyte cell line) during differentiation. Moreover, the ectopic over-expression of 4E-BP1 suppressed PGC-1α expression in white adipocytes, but not in brown adipocytes. Thus, the results of our study indicate that 4E-BP1 may suppress brown adipocyte differentiation and PGC-1α expression in white adipose tissues. © 2013 The Authors Genes to Cells © 2013 by the Molecular Biology Society of Japan and Wiley Publishing Asia Pty Ltd.

Lack of Adipocyte-Fndc5/Irisin Expression and Secretion Reduces Thermogenesis and Enhances Adipogenesis.

PubMed

Pérez-Sotelo, D; Roca-Rivada, A; Baamonde, I; Baltar, J; Castro, A I; Domínguez, E; Collado, M; Casanueva, F F; Pardo, M

2017-11-24

Irisin is a browning-stimulating molecule secreted from the fibronectin type III domain containing 5 precursor (FNDC5) by muscle tissue upon exercise stimulation. Despite its beneficial role, there is an unmet and clamorous need to discern many essential aspects of this protein and its mechanism of action not only as a myokine but also as an adipokine. Here we contribute to address this topic by revealing the nature and role of FNDC5/irisin in adipose tissue. First, we show that FNDC5/irisin expression and secretion are induced by adipocyte differentiation and confirm its over-secretion by human obese visceral (VAT) and subcutaneous (SAT) adipose tissues. Second, we show how secreted factors from human obese VAT and SAT decrease PGC1α, FNDC5 and UCP1 gene expression on differentiating adipocytes; this effect over UCP1 is blunted by blocking irisin in obese secretomes. Finally, by stable gene silencing FNDC5 we reveal that FNDC5-KO adipocytes show reduced UCP1 expression and enhanced adipogenesis.

Effects of 17β-estradiol and progesterone on the production of adipokines in differentiating 3T3-L1 adipocytes: Role of Rho-kinase.

PubMed

Pektaş, Mehtap; Kurt, Akif Hakan; Ün, İsmail; Tiftik, Rukiye Nalan; Büyükafşar, Kansu

2015-04-01

Effect of female sex hormones on the production/release of adipocyte-derived cytokines has been debatable. Furthermore, whether the cellular signaling triggered by these hormones involve Rho-kinase has not been investigated yet. Therefore, in this study, effects of 17β-estradiol and progesterone as well as the Rho-kinase inhibitor, Y-27632 on the level of adipokines such as resistin, adiponectin, leptin, TNF-α and IL-6 were investigated in 3T3-L1-derived adipocytes. Differentiation was induced in the post-confluent preadipocytes by the standard differentiation medium (Dulbecco's modified Eagle's medium with 10% fetal bovine serum together with the mixture of isobutylmethylxanthine, dexamethasone and insulin) in the presence of 17β-estradiol (10(-8)-10(-7)M), progesterone (10(-6)-10(-5)M), the Rho-kinase inhibitor, Y-27632 (10(-5)M) and their combination for 8days. Measurements of the adipokines were performed in the culturing medium by ELISA kits using specific monoclonal antibodies. 17β-estradiol elevated resistin but decreased adiponectin and IL-6 levels; however, it did not alter the concentration of leptin and TNF-α. Y-27632 pretreatment inhibited the rise of resistin and the fall of adiponectin by 17β-estradiol without any effects by its own. Progesterone did not change resistin, leptin and TNF-α level; however, it elevated adiponectin and decreased IL-6 production. Neither 17β-estradiol nor Y-27632 was able to antagonize the increase of adiponectin and the reduction of IL-6 levels by progesterone. While Y-27632 alone lowered IL-6 level, it increased leptin and TNF-α concentration without altering resistin and adiponectin. In conclusion, 17β-estradiol could modify adipokine production in 3T3-L1 adipocytes with the actions some of which involve Rho-kinase mediation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Nuclear factor-κB is a common upstream signal for growth differentiation factor-5 expression in brown adipocytes exposed to pro-inflammatory cytokines and palmitate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hinoi, Eiichi; Iezaki, Takashi; Ozaki, Kakeru

Highlights: • GDF5 expression is up-regulated by IL-1β, TNF-α and palmitate in brown pre-adipocytes. • NF-κB stimulates promoter activity and expression of GDF5 in brown pre-adipocytes. • Recruitment of NF-κB to the GDF5 promoter is facilitated in BAT from ob/ob mice. • An NF-κB inhibitor prevents upregulation of GDF5 expression in brown pre-adipocytes. - Abstract: We have previously demonstrated that genetic and acquired obesity similarly led to drastic upregulation in brown adipose tissue (BAT), rather than white adipose tissue, of expression of both mRNA and corresponding protein for the bone morphogenic protein/growth differentiation factor (GDF) member GDF5 capable of promotingmore » brown adipogenesis. In this study, we evaluated expression profiles of GDF5 in cultured murine brown pre-adipocytes exposed to pro-inflammatory cytokines and free fatty acids (FFAs), which are all shown to play a role in the pathogenesis of obesity. Both interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were effective in up-regulating GDF5 expression in a concentration-dependent manner, while similar upregulation was seen in cells exposed to the saturated FFA palmitate, but not to the unsaturated FFA oleate. In silico analysis revealed existence of the putative nuclear factor-κB (NF-κB) binding site in the 5′-flanking region of mouse GDF5, whereas introduction of NF-κB subunits drastically facilitated both promoter activity and expression of GDF5 in brown pre-adipocytes. Chromatin immunoprecipitation analysis confirmed significant facilitation of the recruitment of NF-κB to the GDF5 promoter in lysed extracts of BAT from leptin-deficient ob/ob obese mice. Upregulation o GDF5 expression was invariably inhibited by an NF-κB inhibitor in cultured brown pre-adipocytes exposed to IL-1β, TNF-α and palmitate. These results suggest that obesity leads to upregulation of GDF5 expression responsible for the promotion of brown adipogenesis through a

Enhanced accumulation of adipocytes in bone marrow stromal cells in the presence of increased extracellular and intracellular [Ca{sup 2+}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, Ryota, E-mail: hryota@juntendo.ac.jp; Katoh, Youichi, E-mail: katoyo@juntendo-urayasu.jp; Nakamura, Kyoko

2012-07-13

Highlights: Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} enhances adipocyte accumulation in the presence of adipogenic inducers. Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} enhances both proliferation and adipocyte differentiation in BMSCs. Black-Right-Pointing-Pointer High [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub o} in BMSCs. Black-Right-Pointing-Pointer An intracellular Ca{sup 2+} chelator suppresses the enhancement in adipocyte accumulation. Black-Right-Pointing-Pointer Controlling [Ca{sup 2+}]{sub o} may govern the balance of adipocyte and osteoblast development. -- Abstract: The bone marrow stroma contains osteoblasts and adipocytes that have a common precursor: the pluripotent mesenchymal stem cell found in bone marrow stromal cells (BMSCs). Local bone marrow Ca{sup 2+}more » levels can reach high concentrations due to bone resorption, which is one of the notable features of the bone marrow stroma. Here, we describe the effects of high [Ca{sup 2+}]{sub o} on the accumulation of adipocytes in the bone marrow stroma. Using primary mouse BMSCs, we evaluated the level of adipocyte accumulation by measuring Oil Red O staining and glycerol-3-phosphate dehydrogenase (GPDH) activity. High [Ca{sup 2+}]{sub o} enhanced the accumulation of adipocytes following treatment with both insulin and dexamethasone together but not in the absence of this treatment. This enhanced accumulation was the result of both the accelerated proliferation of BMSCs and their differentiation into adipocytes. Using the fura-2 method, we also showed that high [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub i}. An intracellular Ca{sup 2+} chelator suppressed the enhancement in adipocyte accumulation due to increased [Ca{sup 2+}]{sub o} in BMSCs. These data suggest a new role for extracellular Ca{sup 2+} in the bone marrow stroma: increased [Ca{sup 2+}]{sub o} induces an increase in [Ca{sup 2+}]{sub i} levels, which in turn enhances the

Alpha-tocopheryl-phosphate regulation of gene expression in pre-adipocytes and adipocytes

USDA-ARS?s Scientific Manuscript database

A correct function of adipocytes in connection with cellular fatty acid loading and release is a vital aspect of energy homeostasis; dysregulation of these reactions can result in obesity and type 2 diabetes mellitus. In addition, adipocytes have been proposed to play a major role in preventing lipo...

Early Planetary Differentiation: Comparative Planetology

NASA Technical Reports Server (NTRS)

Jones, John H.

2006-01-01

We currently have extensive data for four different terrestrial bodies of the inner solar system: Earth, the Moon, Mars, and the Eucrite Parent Body [EPB]. All formed early cores; but all(?) have mantles with elevated concentrations of highly sidero-phile elements, suggestive of the addition of a late "veneer". Two appear to have undergone extensive differentiation consistent with a global magma ocean. One appears to be inconsistent with a simple model of "low-pressure" chondritic differentiation. Thus, there seems to be no single, simple paradigm for understand-ing early differentiation.

Early suppression of adipocyte lipid turnover induces immunometabolic modulation in cancer cachexia syndrome.

PubMed

Henriques, Felipe Santos; Sertié, Rogério Antônio Laurato; Franco, Felipe Oliveira; Knobl, Pamela; Neves, Rodrigo Xavier; Andreotti, Sandra; Lima, Fabio Bessa; Guilherme, Adilson; Seelaender, Marilia; Batista, Miguel Luiz

2017-05-01

Cancer cachexia is a multifactorial syndrome characterized by body weight loss, atrophy of adipose tissue (AT) and systemic inflammation. However, there is limited information regarding the mechanisms of immunometabolic response in AT from cancer cachexia. Male Wistar rats were inoculated with 2 × 10 7 of Walker 256 tumor cells [tumor bearing (TB) rats]. The mesenteric AT (MeAT) was collected on d 0, 4, 7 (early stage), and 14 (cachexia stage) after tumor cell injection. Surgical biopsies for MeAT were obtained from patients who had gastrointestinal cancer with cachexia. Lipolysis showed an early decrease in glycerol release in TB d 4 (TB4) rats in relation to the control, followed by a 6-fold increase in TB14 rats, whereas de novo lipogenesis was markedly lower in the incorporation of glucose into fatty acids in TB14 rats during the development of cachexia. CD11b and CD68 were positive in TB7 and TB14 rats, respectively. In addition, we found cachexia stage results similar to those of animals in MeAT from patients: an increased presence of CD68 + , iNOS2 + , TNFα + , and HSL + cells. In summary, translational analysis of MeAT from patients and an animal model of cancer cachexia enabled us to identify early disruption in Adl turnover and subsequent inflammatory response during the development of cancer cachexia.-Henriques, F. S., Sertié, R. A. L., Franco, F. O., Knobl, P., Neves, R. X., Andreotti, S., Lima, F. B., Guilherme, A., Seelaender, M., Batista, M. L., Jr. Early suppression of adipocyte lipid turnover induces immunometabolic modulation in cancer cachexia syndrome. © FASEB.

Cell-cycle arrest in mature adipocytes impairs BAT development but not WAT browning, and reduces adaptive thermogenesis in mice.

PubMed

Okamatsu-Ogura, Yuko; Fukano, Keigo; Tsubota, Ayumi; Nio-Kobayashi, Junko; Nakamura, Kyoko; Morimatsu, Masami; Sakaue, Hiroshi; Saito, Masayuki; Kimura, Kazuhiro

2017-07-27

We previously reported brown adipocytes can proliferate even after differentiation. To test the involvement of mature adipocyte proliferation in cell number control in fat tissue, we generated transgenic (Tg) mice over-expressing cell-cycle inhibitory protein p27 specifically in adipocytes, using the aP2 promoter. While there was no apparent difference in white adipose tissue (WAT) between wild-type (WT) and Tg mice, the amount of brown adipose tissue (BAT) was much smaller in Tg mice. Although BAT showed a normal cellular morphology, Tg mice had lower content of uncoupling protein 1 (UCP1) as a whole, and attenuated cold exposure- or β3-adrenergic receptor (AR) agonist-induced thermogenesis, with a decrease in the number of mature brown adipocytes expressing proliferation markers. An agonist for the β3-AR failed to increase the number of proliferating brown adipocytes, UCP1 content in BAT, and oxygen consumption in Tg mice, although the induction and the function of beige adipocytes in inguinal WAT from Tg mice were similar to WT mice. These results show that brown adipocyte proliferation significantly contributes to BAT development and adaptive thermogenesis in mice, but not to induction of beige adipocytes.

Phenolic compounds apigenin, hesperidin and kaempferol reduce in vitro lipid accumulation in human adipocytes.

PubMed

Gómez-Zorita, Saioa; Lasa, Arrate; Abendaño, Naiara; Fernández-Quintela, Alfredo; Mosqueda-Solís, Andrea; Garcia-Sobreviela, Maria Pilar; Arbonés-Mainar, Jose M; Portillo, Maria P

2017-11-21

Adipocytes derived from human mesenchymal stem cells (MSCs) are widely used to investigate adipogenesis. Taking into account both the novelty of these MSCs and the scarcity of studies focused on the effects of phenolic compounds, the aim of the present study was to analyze the effect of apigenin, hesperidin and kaempferol on pre-adipocyte and mature adipocytes derived from this type of cells. In addition, the expression of genes involved in TG accumulation was also measured. Pre-adipocytes were cultured from day 0 to day 8 and mature adipocytes for 48 h with the polyphenols at doses of 1, 10 and 25 µM. Apigenin did not show an anti-adipogenic action. Pre-adipocytes treated with hesperidin and kaempferol showed reduced TG content at the three experimental doses. Apigenin did not modify the expression of the main adipogenic genes (c/ebpβ, c/ebpα, pparγ and srebp1c), hesperidin inhibited genes involved in the three phases of adipogenesis (c/ebpβ, srebp1c and perilipin) and kaempferol reduced c/ebpβ. In mature adipocytes, the three polyphenols reduced TG accumulation at the dose of 25 µM, but not at lower doses. All compounds increased mRNA levels of atgl. Apigenin and hesperidin decreased fasn expression. The present study shows the anti-adipogenic effect and delipidating effects of apigenin, hesperidin and kaempferol in human adipocytes derived from hMSCs. While hesperidin blocks all the stages of adipogenesis, kaempferol only inhibits the early stage. Regarding mature adipocytes, the three compounds reduce TG accumulation by activating, at least in part, lipolysis, and in the case of hesperidin and apigenin, also by reducing lipogenesis. The present study shows for the first time the anti-adipogenic effect and delipidating effect of apigenin, hesperidin and kaempferol in human adipocytes derived from MSCs for the first time.

Adipocytes and abdominal aortic aneurysm: Putative potential role of adipocytes in the process of AAA development.

PubMed

Kugo, Hirona; Moriyama, Tatsuya; Zaima, Nobuhiro

2018-01-15

Background Adipose tissue plays a role in the storage of excess energy as triglycerides (TGs). Excess fat accumulation causes various metabolic and cardiovascular diseases. It has been reported that ectopic fat deposition and excess TG accumulation in non-adipose tissue might be important predictors of cardiometabolic and vascular risk. For example, ectopic fat in perivascular tissue promotes atherosclerotic plaque formation in the arterial wall. Objective Recently, it has been reported that ectopic fat (adipocyte) in the vascular wall of an abdominal aortic aneurysm (AAA) is present in both human and experimental animal models. The pathological significance of adipocytes in the AAA wall has not been fully understood. In this review, we summarized the functions of adipocytes and discussed potential new drugs that target vascular adipocytes for AAA treatment. Result Previous studies suggest that adipocytes in vascular wall play an important role in the development of AAA. Conclusion Adipocytes in the vascular wall could be novel targets for the development of AAA therapeutic drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Quercetin, a functional compound of onion peel, remodels white adipocytes to brown-like adipocytes.

PubMed

Lee, Sang Gil; Parks, John S; Kang, Hye Won

2017-04-01

Adipocyte browning is a promising strategy for obesity prevention. Using onion-peel-derived extracts and their bioactive compounds, we demonstrate that onion peel, a by-product of onion, can change the characteristics of white adipocytes to those of brown-like adipocytes in the white adipose tissue of mice and 3T3-L1 cells. The expression of the following brown adipose tissue-specific genes was increased in the retroperitoneal and subcutaneous adipose tissues of 0.5% onion-peel-extract-fed mice: PR domain-containing 16, peroxisome proliferator-activated receptor gamma coactivator 1α, uncoupling protein 1, fibroblast growth factor 21 and cell death-inducing DFFA-like effector. In 3T3-L1 adipocytes, onion peel extract induced the expression of brown adipose tissue-specific genes and increased the expression of carnitine palmitoyltransferase 1α. This effect was supported by decreased lipid levels and multiple small-sized lipid droplets. The ethyl acetate fraction of the onion peel extract that contained the highest proportion of hydrophobic molecules showed the same browning effect in 3T3-L1 adipocytes. A high-performance liquid chromatography analysis further identified quercetin as a functional compound in the browning effect of onion peel. The quercetin-associated browning effect was mediated in part by the activation of AMP-activated protein kinase. In summary, our study provides the first demonstration of the browning effects of onion peel and quercetin using both animal and cell models. This result indicates that onion peel has the potential to remodel the characteristics of white adipocytes to those of brown-like adipocytes. Copyright © 2017 Elsevier Inc. All rights reserved.

Lipid phosphate phosphatase 3 regulates adipocyte sphingolipid synthesis, but not developmental adipogenesis or diet-induced obesity in mice.

PubMed

Federico, Lorenzo; Yang, Liping; Brandon, Jason; Panchatcharam, Manikandan; Ren, Hongmei; Mueller, Paul; Sunkara, Manjula; Escalante-Alcalde, Diana; Morris, Andrew J; Smyth, Susan S

2018-01-01

Dephosphorylation of phosphatidic acid (PA) is the penultimate step in triglyceride synthesis. Adipocytes express soluble intracellular PA-specific phosphatases (Lipins) and broader specificity membrane-associated lipid phosphate phosphatases (LPPs) that can also dephosphorylate PA. Inactivation of lipin1 causes lipodystrophy in mice due to defective developmental adipogenesis. Triglyceride synthesis is diminished but not ablated by inactivation of lipin1 in differentiated adipocytes implicating other PA phosphatases in this process. To investigate the possible role of LPPs in adipocyte lipid metabolism and signaling we made mice with adipocyte-targeted inactivation of LPP3 encoded by the Plpp3(Ppap2b) gene. Adipocyte LPP3 deficiency resulted in blunted ceramide and sphingomyelin accumulation during diet-induced adipose tissue expansion, accumulation of the LPP3 substrate sphingosine 1- phosphate, and reduced expression of serine palmitoyl transferase. However, adiposity was unaffected by LPP3 deficiency on standard, high fat diet or Western diets, although Western diet-fed mice with adipocyte LPP3 deficiency exhibited improved glucose tolerance. Our results demonstrate functional compartmentalization of lipid phosphatase activity in adipocytes and identify an unexpected role for LPP3 in the regulation of diet-dependent sphingolipid synthesis that may impact on insulin signaling.

Adipocyte-Macrophage Cross-Talk in Obesity.

PubMed

Engin, Ayse Basak

2017-01-01

Obesity is characterized by the chronic low-grade activation of the innate immune system. In this respect, macrophage-elicited metabolic inflammation and adipocyte-macrophage interaction has a primary importance in obesity. Large amounts of macrophages are accumulated by different mechanisms in obese adipose tissue. Hypertrophic adipocyte-derived chemotactic monocyte chemoattractant protein-1 (MCP-1)/C-C chemokine receptor 2 (CCR2) pathway also promotes more macrophage accumulation into the obese adipose tissue. However, increased local extracellular lipid concentrations is a final mechanism for adipose tissue macrophage accumulation. A paracrine loop involving free fatty acids and tumor necrosis factor-alpha (TNF-alpha) between adipocytes and macrophages establishes a vicious cycle that aggravates inflammatory changes in the adipose tissue. Adipocyte-specific caspase-1 and production of interleukin-1beta (IL-1beta) by macrophages; both adipocyte and macrophage induction by toll like receptor-4 (TLR4) through nuclear factor-kappaB (NF-kappaB) activation; free fatty acid-induced and TLR-mediated activation of c-Jun N-terminal kinase (JNK)-related pro-inflammatory pathways in CD11c+ immune cells; are effective in macrophage accumulation and in the development of adipose tissue inflammation. Old adipocytes are removed by macrophages through trogocytosis or sending an "eat me" signal. The obesity-induced changes in adipose tissue macrophage numbers are mainly due to increases in the triple-positive CD11b+ F4/80+ CD11c+ adipose tissue macrophage subpopulation. The ratio of M1-to-M2 macrophages is increased in obesity. Furthermore, hypoxia along with higher concentrations of free fatty acids exacerbates macrophage-mediated inflammation in obesity. The metabolic status of adipocytes is a major determinant of macrophage inflammatory output. Macrophage/adipocyte fatty-acid-binding proteins act at the interface of metabolic and inflammatory pathways. Both macrophages and

Transcription factor PU.1 is expressed in white adipose and inhibits adipocyte differentiation

USDA-ARS?s Scientific Manuscript database

PU.1 transcription factor is a critical regulator of hematopoiesis and leukemogenesis. Because PU.1 interacts with transcription factors GATA-2 and C/EBPa, both of which are involved in the regulation of adipogenesis, we investigated whether PU.1 also plays a role in the regulation of adipocyte diff...

Hyperspectral and differential CARS microscopy for quantitative chemical imaging in human adipocytes

PubMed Central

Di Napoli, Claudia; Pope, Iestyn; Masia, Francesco; Watson, Peter; Langbein, Wolfgang; Borri, Paola

2014-01-01

In this work, we demonstrate the applicability of coherent anti-Stokes Raman scattering (CARS) micro-spectroscopy for quantitative chemical imaging of saturated and unsaturated lipids in human stem-cell derived adipocytes. We compare dual-frequency/differential CARS (D-CARS), which enables rapid imaging and simple data analysis, with broadband hyperspectral CARS microscopy analyzed using an unsupervised phase-retrieval and factorization method recently developed by us for quantitative chemical image analysis. Measurements were taken in the vibrational fingerprint region (1200–2000/cm) and in the CH stretch region (2600–3300/cm) using a home-built CARS set-up which enables hyperspectral imaging with 10/cm resolution via spectral focussing from a single broadband 5 fs Ti:Sa laser source. Through a ratiometric analysis, both D-CARS and phase-retrieved hyperspectral CARS determine the concentration of unsaturated lipids with comparable accuracy in the fingerprint region, while in the CH stretch region D-CARS provides only a qualitative contrast owing to its non-linear behavior. When analyzing hyperspectral CARS images using the blind factorization into susceptibilities and concentrations of chemical components recently demonstrated by us, we are able to determine vol:vol concentrations of different lipid components and spatially resolve inhomogeneities in lipid composition with superior accuracy compared to state-of-the art ratiometric methods. PMID:24877002

RPL13A and EEF1A1 Are Suitable Reference Genes for qPCR during Adipocyte Differentiation of Vascular Stromal Cells from Patients with Different BMI and HOMA-IR.

PubMed

Gentile, Adriana-Mariel; Lhamyani, Said; Coín-Aragüez, Leticia; Oliva-Olivera, Wilfredo; Zayed, Hatem; Vega-Rioja, Antonio; Monteseirin, Javier; Romero-Zerbo, Silvana-Yanina; Tinahones, Francisco-José; Bermúdez-Silva, Francisco-Javier; El Bekay, Rajaa

2016-01-01

Real-time or quantitative PCR (qPCR) is a useful technique that requires reliable reference genes for data normalization in gene expression analysis. Adipogenesis is among the biological processes suitable for this technique. The selection of adequate reference genes is essential for qPCR gene expression analysis of human Vascular Stromal Cells (hVSCs) during their differentiation into adipocytes. To the best of our knowledge, there are no studies validating reference genes for the analyses of visceral and subcutaneous adipose tissue hVSCs from subjects with different Body Mass Index (BMI) and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index. The present study was undertaken to analyze this question. We first analyzed the stability of expression of five potential reference genes: CYC, GAPDH, RPL13A, EEF1A1, and 18S ribosomal RNA, during in vitro adipogenic differentiation, in samples from these types of patients. The expression of RPL13A and EEF1A1 was not affected by differentiation, thus being these genes the most stable candidates, while CYC, GAPDH, and 18S were not suitable for this sort of analysis. This work highlights that RPL13A and EEF1A1 are good candidates as reference genes for qPCR analysis of hVSCs differentiation into adipocytes from subjects with different BMI and HOMA-IR.

RPL13A and EEF1A1 Are Suitable Reference Genes for qPCR during Adipocyte Differentiation of Vascular Stromal Cells from Patients with Different BMI and HOMA-IR

PubMed Central

Gentile, Adriana-Mariel; Lhamyani, Said; Coín-Aragüez, Leticia; Oliva-Olivera, Wilfredo; Zayed, Hatem; Vega-Rioja, Antonio; Monteseirin, Javier; Romero-Zerbo, Silvana-Yanina; Tinahones, Francisco-José; Bermúdez-Silva, Francisco-Javier; El Bekay, Rajaa

2016-01-01

Real-time or quantitative PCR (qPCR) is a useful technique that requires reliable reference genes for data normalization in gene expression analysis. Adipogenesis is among the biological processes suitable for this technique. The selection of adequate reference genes is essential for qPCR gene expression analysis of human Vascular Stromal Cells (hVSCs) during their differentiation into adipocytes. To the best of our knowledge, there are no studies validating reference genes for the analyses of visceral and subcutaneous adipose tissue hVSCs from subjects with different Body Mass Index (BMI) and Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) index. The present study was undertaken to analyze this question. We first analyzed the stability of expression of five potential reference genes: CYC, GAPDH, RPL13A, EEF1A1, and 18S ribosomal RNA, during in vitro adipogenic differentiation, in samples from these types of patients. The expression of RPL13A and EEF1A1 was not affected by differentiation, thus being these genes the most stable candidates, while CYC, GAPDH, and 18S were not suitable for this sort of analysis. This work highlights that RPL13A and EEF1A1 are good candidates as reference genes for qPCR analysis of hVSCs differentiation into adipocytes from subjects with different BMI and HOMA-IR. PMID:27304673

Obestatin regulates adipocyte function and protects against diet-induced insulin resistance and inflammation.

PubMed

Granata, Riccarda; Gallo, Davide; Luque, Raul M; Baragli, Alessandra; Scarlatti, Francesca; Grande, Cristina; Gesmundo, Iacopo; Córdoba-Chacón, Jose; Bergandi, Loredana; Settanni, Fabio; Togliatto, Gabriele; Volante, Marco; Garetto, Stefano; Annunziata, Marta; Chanclón, Belén; Gargantini, Eleonora; Rocchietto, Stefano; Matera, Lina; Datta, Giacomo; Morino, Mario; Brizzi, Maria Felice; Ong, Huy; Camussi, Giovanni; Castaño, Justo P; Papotti, Mauro; Ghigo, Ezio

2012-08-01

The metabolic actions of the ghrelin gene-derived peptide obestatin are still unclear. We investigated obestatin effects in vitro, on adipocyte function, and in vivo, on insulin resistance and inflammation in mice fed a high-fat diet (HFD). Obestatin effects on apoptosis, differentiation, lipolysis, and glucose uptake were determined in vitro in mouse 3T3-L1 and in human subcutaneous (hSC) and omental (hOM) adipocytes. In vivo, the influence of obestatin on glucose metabolism was assessed in mice fed an HFD for 8 wk. 3T3-L1, hSC, and hOM preadipocytes and adipocytes secreted obestatin and showed specific binding for the hormone. Obestatin prevented apoptosis in 3T3-L1 preadipocytes by increasing phosphoinositide 3-kinase (PI3K)/Akt and extracellular signal-regulated kinase (ERK)1/2 signaling. In both mice and human adipocytes, obestatin inhibited isoproterenol-induced lipolysis, promoted AMP-activated protein kinase phosphorylation, induced adiponectin, and reduced leptin secretion. Obestatin also enhanced glucose uptake in either the absence or presence of insulin, promoted GLUT4 translocation, and increased Akt phosphorylation and sirtuin 1 (SIRT1) protein expression. Inhibition of SIRT1 by small interfering RNA reduced obestatin-induced glucose uptake. In HFD-fed mice, obestatin reduced insulin resistance, increased insulin secretion from pancreatic islets, and reduced adipocyte apoptosis and inflammation in metabolic tissues. These results provide evidence of a novel role for obestatin in adipocyte function and glucose metabolism and suggest potential therapeutic perspectives in insulin resistance and metabolic dysfunctions.

An In Vitro Model to Probe the Regulation of Adipocyte Differentiation under Hyperglycemia

PubMed Central

Shilpa, Kusampudi; Dinesh, Thangaraj

2013-01-01

Background The aim of this study was an in vitro investigation of the effect of high glucose concentration on adipogenesis, as prolonged hyperglycemia alters adipocyte differentiation. Methods 3T3-L1 preadipocytes differentiated in the presence of varying concentrations of glucose (25, 45, 65, 85, and 105 mM) were assessed for adipogenesis using AdipoRed (Lonza) assay. Cell viability and proliferation were measured using MTT reduction and [3H] thymidine incorporation assay. The extent of glucose uptake and glycogen synthesis were measured using radiolabelled 2-deoxy-D-[1-3H] glucose and [14C]-UDP-glucose. The gene level expression was evaluated using reverse transcription-polymerase chain reaction and protein expression was studied using Western blot analysis. Results Glucose at 105 mM concentration was observed to inhibit adipogenesis through inhibition of CCAAT-enhancer-binding proteins, sterol regulatory element-binding protein, peroxisome proliferator-activated receptor and adiponectin. High concentration of glucose induced stress by increasing levels of toll-like receptor 4, nuclear factor κB and tumor necrosis factor α thereby generating activated preadipocytes. These cells entered the state of hyperplasia through inhibition of p27 and proliferation was found to increase through activation of protein kinase B via phosphoinositide 3 kinase dependent pathway. This condition inhibited insulin signaling through decrease in insulin receptor β. Although the glucose transporter 4 (GLUT4) protein remained unaltered with the glycogen synthesis inhibited, the cells were found to exhibit an increase in glucose uptake via GLUT1. Conclusion Adipogenesis in the presence of 105 mM glucose leads to an uncontrolled proliferation of activated preadipocytes providing an insight towards understanding obesity. PMID:23807920

Maf promotes osteoblast differentiation in mice by mediating the age-related switch in mesenchymal cell differentiation

PubMed Central

Nishikawa, Keizo; Nakashima, Tomoki; Takeda, Shu; Isogai, Masashi; Hamada, Michito; Kimura, Ayako; Kodama, Tatsuhiko; Yamaguchi, Akira; Owen, Michael J.; Takahashi, Satoru; Takayanagi, Hiroshi

2010-01-01

Aging leads to the disruption of the homeostatic balance of multiple biological systems. In bone marrow multipotent mesenchymal cells undergo differentiation into various anchorage-dependent cell types, including osteoblasts and adipocytes. With age as well as with treatment of antidiabetic drugs such as thiazolidinediones, mesenchymal cells favor differentiation into adipocytes, resulting in an increased number of adipocytes and a decreased number of osteoblasts, causing osteoporosis. The mechanism behind this differentiation switch is unknown. Here we show an age-related decrease in the expression of Maf in mouse mesenchymal cells, which regulated mesenchymal cell bifurcation into osteoblasts and adipocytes by cooperating with the osteogenic transcription factor Runx2 and inhibiting the expression of the adipogenic transcription factor Pparg. The crucial role of Maf in both osteogenesis and adipogenesis was underscored by in vivo observations of delayed bone formation in perinatal Maf–/– mice and an accelerated formation of fatty marrow associated with bone loss in aged Maf+/– mice. This study identifies a transcriptional mechanism for an age-related switch in cell fate determination and may provide a molecular basis for novel therapeutic strategies against age-related bone diseases. PMID:20877012

Anti-obesity effects of Arctii Fructus (Arctium lappa) in white/brown adipocytes and high-fat diet-induced obese mice.

PubMed

Han, Yo-Han; Kee, Ji-Ye; Kim, Dae-Seung; Park, Jinbong; Jeong, Mi-Young; Mun, Jung-Geon; Park, Sung-Joo; Lee, Jong-Hyun; Um, Jae-Young; Hong, Seung-Heon

2016-12-07

Arctii Fructus is traditionally used in oriental pharmacies as an anti-inflammatory medicine. Although several studies have shown its anti-inflammatory effects, there have been no reports on its use in obesity related studies. In this study, the anti-obesity effect of Arctii Fructus was investigated in high-fat diet (HFD)-induced obese mice, and the effect was confirmed in white and primary cultured brown adipocytes. Arctii Fructus inhibited weight gain and reduced the mass of white adipose tissue in HFD-induced obese mice. Serum levels of triglyceride and LDL-cholesterol were reduced, and HDL-cholesterol was increased in the Arctii Fructus treated group. In 3T3-L1 cells, a water extract (WAF) and 70% EtOH extract (EtAF) of Arctii Fructus significantly inhibited adipogenesis and suppressed the expression of proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha. In particular, EtAF activated the phosphorylation of AMP-activated protein kinase. On the other hand, uncoupling protein 1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, known as brown adipocytes specific genes, were increased in primary cultured brown adipocytes by WAF and EtAF. This study shows that Arctii Fructus prevents the development of obesity through the inhibition of white adipocyte differentiation and activation of brown adipocyte differentiation which suggests that Arctii Fructus could be an effective therapeutic for treating or preventing obesity.

A heterogeneous lineage origin underlies the phenotypic and molecular differences of white and beige adipocytes

PubMed Central

Liu, Weiyi; Shan, Tizhong; Yang, Xin; Liang, Sandra; Zhang, Pengpeng; Liu, Yaqin; Liu, Xiaoqi; Kuang, Shihuan

2013-01-01

Summary A worldwide epidemic of obesity and its associated metabolic disorders raise the significance of adipocytes, their origins and characteristics. Our previous study has demonstrated that interscapular brown adipose tissue (BAT), but not intramuscular adipose, is derived from the Pax3-expressing cell lineage. Here, we show that various depots of subcutaneous (SAT) and visceral adipose tissue (VAT) are highly heterogeneous in the Pax3 lineage origin. Interestingly, the relative abundance of Pax3 lineage cells in SAT depots is inversely correlated to expression of BAT signature genes including Prdm16, Pgc1a (Ppargc1a) and Ucp1. FACS analysis further demonstrates that adipocytes differentiated from non-Pax3 lineage preadipocytes express higher levels of BAT and beige adipocyte signature genes compared with the Pax3 lineage adipocytes within the same depots. Although both Pax3 and non-Pax3 lineage preadipocytes can give rise to beige adipocytes, the latter contributes more significantly. Consistently, genetic ablation of Pax3 lineage cells in SAT leads to increased expression of beige cell markers. Finally, non-Pax3 lineage beige adipocytes are more responsive to cAMP-agonist-induced Ucp1 expression. Taken together, these results demonstrate widespread heterogeneity in Pax3 lineage origin, and its inverse association with BAT gene expression within and among subcutaneous adipose depots. PMID:23781029

Application of adipocyte-derived stem cells in treatment of cutaneous radiation syndrome.

PubMed

Riccobono, Diane; Agay, Diane; Scherthan, Harry; Forcheron, Fabien; Vivier, Mylène; Ballester, Bruno; Meineke, Viktor; Drouet, Michel

2012-08-01

Cutaneous radiation syndrome caused by local high dose irradiation is characterized by delayed outcome and incomplete healing. Recent therapeutic management of accidentally irradiated burn patients has suggested the benefit of local cellular therapy using mesenchymal stem cell grafting. According to the proposed strategy of early treatment, large amounts of stem cells would be necessary in the days following exposure and hospitalization, which would require allogeneic stem cells banking. In this context, the authors compared the benefit of local autologous and allogeneic adipocyte-derived stem cell injection in a large animal model. Minipigs were locally irradiated using a 60Co gamma source at a dose of 50 Gy and divided into three groups. Two groups were grafted with autologous (n = 5) or allogeneic (n = 5) adipocyte-derived stem cells four times after the radiation exposure, whereas the control group received the vehicle without cells (n = 8). A clinical score was elaborated to compare the efficiency of the three treatments. All controls exhibited local inflammatory injuries leading to a persistent painful necrosis, thus mimicking the clinical evolution in human victims. In the autologous adipocyte-derived stem cells group, skin healing without necrosis or uncontrollable pain was observed. In contrast, the clinical outcome was not significantly different in the adipocyte-derived stem cell allogeneic group when compared with controls. This study suggests that autologous adipocyte-derived stem cell grafting improves cutaneous radiation syndrome wound healing, whereas allogeneic adipocyte derived stem cells do not. Further studies will establish whether manipulation of allogeneic stem cells will improve their therapeutic potential.

Suppression of lipin-1 expression increases monocyte chemoattractant protein-1 expression in 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Nobuhiko, E-mail: ntkhs@hoku-iryo-u.ac.jp; Division of Gastroenterology and Hematology/Oncology, Department of Medicine, Asahikawa Medical University, 2-1-1-1 Midorigaoka-Higashi, Asahikawa, Hokkaido 078-8510; Yoshizaki, Takayuki

2011-11-11

Highlights: Black-Right-Pointing-Pointer Lipin-1 affects lipid metabolism, adipocyte differentiation, and transcription. Black-Right-Pointing-Pointer Adipose lipin-1 expression is reduced in obesity. Black-Right-Pointing-Pointer Lipin-1 depletion using siRNA in 3T3-L1 adipocytes increased MCP-1 expression. Black-Right-Pointing-Pointer Lipin-1 is involved in adipose inflammation. -- Abstract: Lipin-1 plays a crucial role in the regulation of lipid metabolism and cell differentiation in adipocytes. Expression of adipose lipin-1 is reduced in obesity, and metabolic syndrome. However, the significance of this reduction remains unclear. This study investigated if and how reduced lipin-1 expression affected metabolism. We assessed mRNA expression levels of various genes related to adipocyte metabolism in lipin-1-depleted 3T3-L1 adipocytesmore » by introducing its specific small interfering RNA. In lipin-1-depleted adipocytes, mRNA and protein expression levels of monocyte chemoattractant protein-1 (MCP-1) were significantly increased, although the other genes tested were not altered. The conditioned media from the cells promoted monocyte chemotaxis. The increase in MCP-1 expression was prevented by treatment with quinazoline or salicylate, inhibitors of nuclear factor-{kappa}B activation. Because MCP-1 is related to adipose inflammation and systemic insulin resistance, these results suggest that a reduction in adipose lipin-1 in obesity may exacerbate adipose inflammation and metabolism.« less

Brazilein from Caesalpinia sappan L. Antioxidant Inhibits Adipocyte Differentiation and Induces Apoptosis through Caspase-3 Activity and Anthelmintic Activities against Hymenolepis nana and Anisakis simplex

PubMed Central

Liang, Chia-Hua; Chan, Leong-Perng; Chou, Tzung-Han; Chiang, Feng-Yu; Yen, Chuan-Min; Chen, Pin-Ju; Ding, Hsiou-Yu

2013-01-01

Brazilein, a natural, biologically active compound from Caesalpinia sappan L., has been shown to exhibit anti-inflammatory and antioxidant properties and to inhibit the growth of several cancer cells. This study verifies the antioxidant and antitumor characteristics of brazilein in skin cancer cells and is the first time to elucidate the inhibition mechanism of adipocyte differentiation, cestocidal activities against Hymenolepis nana, and reduction of spontaneous movement in Anisakis simplex. Brazilein exhibits an antioxidant capacity as well as the ability to scavenge DPPH• and ABTS•+ free radicals and to inhibit lipid peroxidation. Brazilein inhibited intracellular lipid accumulation during adipocyte differentiation in 3T3-L1 cells and suppressed the induction of peroxisome proliferator-activated receptor γ (PPARγ), the master regulator of adipogenesis, suggesting that brazilein presents the antiobesity effects. The toxic effects of brazilein were evaluated in terms of cell viability, induction of apoptosis, and the activity of caspase-3 in BCC cells. The inhibition of the growth of skin cancer cells (A431, BCC, and SCC25) by brazilein is greater than that of human skin malignant melanoma (A375) cells, mouse leukemic monocyte macrophage (RAW 264.7 cells), and noncancerous cells (HaCaT and BNLCL2 cells). The anthelmintic activities of brazilein against Hymenolepis nana are better than those of Anisakis simplex. PMID:23554834

Pulicaria jaubertii extract prevents triglyceride deposition in 3T3-L1 adipocytes

USDA-ARS?s Scientific Manuscript database

Currently, levels of obesity in Middle Eastern countries are increasing. Phytochemicals have anti-obesogenic properties as evidenced by prevention of adipocyte differentiation. In Yemen, Pulicaria jaubertii E.Gamal-Eldin (PJ) is a food additive and a traditional medicine. We tested the ability of ex...

PPAR gamma partial agonist, KR-62776, inhibits adipocyte differentiation via activation of ERK.

PubMed

Kim, J; Han, D C; Kim, J M; Lee, S Y; Kim, S J; Woo, J R; Lee, J W; Jung, S-K; Yoon, K S; Cheon, H G; Kim, S S; Hong, S H; Kwon, B-M

2009-05-01

Indenone KR-62776 acts as an agonist of PPAR gamma without inducing obesity in animal models and cells. X-ray crystallography reveals that the indenone occupies the binding pocket in a different manner than rosiglitazone. 2-Dimensional gel-electrophoresis showed that the expression of 42 proteins was altered more than 2.0-fold between KR-62776- or rosiglitazone-treated adipocyte cells and control cells. Rosiglitazone down-regulated the expression of ERK1/2 and suppressed the phosphorylation of ERK1/2 in these cells. However, the expression of ERK1/2 was up-regulated in KR-62776-treated cells. Phosphorylated ERK1/2, activated by indenone, affects the localization of PPAR gamma, suggesting a mechanism for indenone-inhibition of adipogenesis in 3T3-L1 preadipocyte cells. The preadipocyte cells are treated with ERK1/2 inhibitor PD98059, a large amount of the cells are converted to adipocyte cells. These results support the conclusion that the localization of PPAR gamma is one of the key factors explaining the biological responses of the ligands.

Cadmium modulates adipocyte functions in metallothionein-null mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kawakami, Takashige; Nishiyama, Kaori; Kadota, Yoshito

2013-11-01

Our previous study has demonstrated that exposure to cadmium (Cd), a toxic heavy metal, causes a reduction of adipocyte size and the modulation of adipokine expression. To further investigate the significance of the Cd action, we studied the effect of Cd on the white adipose tissue (WAT) of metallothionein null (MT{sup −/−}) mice, which cannot form atoxic Cd–MT complexes and are used for evaluating Cd as free ions, and wild type (MT{sup +/+}) mice. Cd administration more significantly reduced the adipocyte size of MT{sup −/−} mice than that of MT{sup +/+} mice. Cd exposure also induced macrophage recruitment to WATmore » with an increase in the expression level of Ccl2 (MCP-1) in the MT{sup −/−} mice. The in vitro exposure of Cd to adipocytes induce triglyceride release into culture medium, decrease in the expression levels of genes involved in fatty acid synthesis and lipid hydrolysis at 24 h, and at 48 h increase in phosphorylation of the lipid-droplet-associated protein perilipin, which facilitates the degradation of stored lipids in adipocytes. Therefore, the reduction in adipocyte size by Cd may arise from an imbalance between lipid synthesis and lipolysis. In addition, the expression levels of leptin, adiponectin and resistin decreased in adipocytes. Taken together, exposure to Cd may induce unusually small adipocytes and modulate the expression of adipokines differently from the case of physiologically small adipocytes, and may accelerate the risk of developing insulin resistance and type 2 diabetes. - Highlights: • Cd causes a marked reduction in adipocyte size in MT-null mice. • Cd enhances macrophage migration into adipose tissue and disrupt adipokine secretion. • MT gene alleviates Cd-induced adipocyte dysfunctions. • Cd enhances the degradation of stored lipids in adipocytes, mediated by perilipin. • Cd induces unusually small adipocytes and the abnormal expression of adipokines.« less

Transplantation and differentiation of donor cells in the cloned pigs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shimada, Arata; Tomii, Ryo; Kano, Koichiro

2006-06-02

The application of nuclear transfer technology is an interesting approach to investigate stem and progenitor cell transplantation therapy. If stem cells are used as a nuclear donor, donor cells can engraft into cloned animals without histocompatible problems. However, it is still uncertain whether donor cells can engraft to cloned animal and differentiate in vivo. To address this problem, we transplanted donor cells to dermal tissues of cloned pigs developed by using preadipocytes as donor cells. Preadipocytes are adipocytic progenitor which can differentiate to mature adipocytes in vitro. We showed that the donor preadipocytes were successfully transplanted into the cloned pigsmore » without immune rejection and they differentiated into mature adipocytes in vivo 3 weeks after transplantation. In contrast, allogenic control preadipocytes, which can differentiate in vitro, did not differentiate in vivo. These results indicate that donor progenitor cells can differentiate in cloned animal.« less

St. John’s Wort inhibits insulin signaling in murine and human adipocytes

PubMed Central

Richard, Allison J.; Amini, Zhaleh J.; Ribnicky, David M.; Stephens, Jacqueline M.

2012-01-01

Adipocytes are insulin-sensitive cells that play a major role in energy homeostasis. Obesity is the primary disease of fat cells and a major risk factor for the development of Type 2 diabetes, cardiovascular disease, and metabolic syndrome. The use of botanicals in the treatment of metabolic diseases is an emerging area of research. In previous studies, we screened over 425 botanical extracts for their ability to modulate adipogenesis and insulin sensitivity. We identified St. John’s Wort (SJW) extracts as inhibitors of adipogenesis of 3T3-L1 cells and demonstrated that these extracts also inhibited insulin-sensitive glucose uptake in mature fat cells. In these follow-up studies we have further characterized the effects of SJW on insulin action in both murine and human fat cells. We have shown that SJW also attenuates insulin-sensitive glucose uptake in human adipocytes. Moreover, SJW inhibits IRS-1 tyrosine phosphorylation in both murine and human fat cells. Botanical extracts are complex mixtures. Many bioactive compounds have been identified in SJW, including hypericin (HI) and hyperforin (HF). We have examined the ability of HI and HF, purified from SJW, to modulate adipocyte development and insulin action in mature adipocytes. Our novel studies indicate that the profound effects of SJW on adipogenesis, IRS-1 activation, and insulin-stimulated glucose uptake are not mediated by HI and/or HF. Nonetheless, we propose that extracts of SJW may contribute to adipocyte related diseases by limiting differentiation of preadipocytes and significantly inducing insulin resistance in mature fat cells. PMID:22198320

Adipocyte and leptin accumulation in tumor-induced thymic involution.

PubMed

Lamas, Alejandro; Lopez, Elena; Carrio, Roberto; Lopez, Diana M

2016-01-01

Cell-mediated immunity is an important defense mechanism against pathogens and developing tumor cells. The thymus is the main lymphoid organ involved in the formation of the cell-mediated immune response by the maturation and differentiation of lymphocytes that travel from the bone marrow, through the lymphatic ducts, to become T lymphocytes. Thymic involution has been associated with aging; however, other factors such as obesity, viral infection and tumor development have been shown to increase the rate of shrinkage of this organ. The heavy infiltration of adipocyte fat cells has been reported in the involuted thymuses of aged mice. In the present study, the possible accumulation of such cells in the thymus during tumorigenesis was examined by immunohistochemistry. A significant number of adipocytes around and infiltrating the thymuses of tumor-bearing mice was observed. Leptin is a pro-inflammatory adipocytokine that enhances thymopoiesis and modulates T cell immune responses. The levels of leptin and adiponectin, another adipocytokine that has anti-inflammatory properties, were examined by western blot analysis. While no changes were observed in the amounts of adiponectin present in the thymuses of the normal and tumor-bearing mice, significantly higher levels of leptin were detected in the thymocytes of the tumor-bearing mice. This correlated with an increase in the expression of certain cytokines, such as interleukin (IL)-2, interferon (IFN)-γ and granulocyte-macrophage colony-stimulating factor (GM-CSF). The co-culture of thymocytes isolated from normal mice with ex vivo isolated adipocytes from tumor-bearing mice yielded similar results. Our findings suggest that the infiltration and accumulation of adipocytes in the thymuses of tumor-bearing mice play an important role in their altered morphology and functions.

The novel anti-adipogenic effect and mechanisms of action of SGI-1776, a Pim-specific inhibitor, in 3T3-L1 adipocytes.

PubMed

Park, Yu-Kyoung; Hong, Victor Sukbong; Lee, Tae-Yoon; Lee, Jinho; Choi, Jong-Soon; Park, Dong-Soon; Park, Gi-Young; Jang, Byeong-Churl

2016-01-01

The proviral integration site for moloney murine leukemia virus (Pim) kinases, consisting of Pim-1, Pim-2 and Pim-3, belongs to a family of serine/threonine kinases that are involved in controlling cell growth and differentiation. Pim kinases are emerging as important mediators of adipocyte differentiation. SGI-1776, an inhibitor of Pim kinases, is widely used to assess the physiological roles of Pim kinases, particularly cell functions. In the present study, we examined the effects of SGI-1776 on adipogenesis. The anti‑adipogenic effect of SGI‑1776 was measured by Oil Red O staining and AdipoRed assays. The effect of SGI‑1776 on the growth of 3T3‑L1 adipocytes was determined by cell count analysis. The effects of SGI‑1776 on the protein and mRNA expression of adipogenesis-related proteins and adipokines in 3T3‑L1 adipocytes were also evaluated by western blot analysis and RT‑PCR, respectively. Notably, SGI-1776 markedly inhibited lipid accumulation during the differentiation of 3T3-L1 preadipocytes into adipocytes. On a mechanistic level, SGI-1776 inhibited not only the expression of CCAAT/enhancer-binding protein-α (C/EBP-α), peroxisome proliferator-activated receptor-γ (PPAR-γ) and fatty acid synthase (FAS), but also the phosphorylation of signal transducer and activator of transcription-3 (STAT-3). Moreover, SGI-1776 decreased the expression of adipokines, including the expression of leptin and regulated on activation, normal T cell expressed and secreted (RANTES) during adipocyte differentiation. These findings demonstrate that SGI-1776 inhibits adipogenesis by downregulating the expression and/or phosphorylation levels of C/EBP-α, PPAR-γ, FAS and STAT-3.

Gene expression profiling of 3T3-L1 adipocytes exposed to phloretin.

PubMed

Hassan, Meryl; El Yazidi, Claire; Malezet-Desmoulins, Christiane; Amiot, Marie-Josèphe; Margotat, Alain

2010-07-01

Adipocyte dysfunction plays a major role in the outcome of obesity, insulin resistance and related cardiovascular complications. Thus, considerable efforts are underway in the pharmaceutical industry to find molecules that target the now well-documented pleiotropic functions of adipocyte. We previously reported that the dietary flavonoid phloretin enhances 3T3-L1 adipocyte differentiation and adiponectin expression at least in part through PPAR gamma activation. The present study was designed to further characterize the molecular mechanisms underlying the phloretin-mediated effects on 3T3-L1 adipocytes using microarray technology. We show that phloretin positively regulates the expression of numerous genes involved in lipogenesis and triglyceride storage, including GLUT4, ACSL1, PEPCK1, lipin-1 and perilipin (more than twofold). The expression of several genes encoding adipokines, in addition to adiponectin and its receptor, is positively or negatively regulated in a way that suggests a possible reduction in systemic insulin resistance and obesity-associated inflammation. Improvement of insulin sensitivity is also suggested by the overexpression of genes associated with insulin signal transduction, such as CAP, PDK1 and Akt2. Many of these genes are PPAR gamma targets, confirming the involvement of PPAR gamma pathway in the phloretin effects on adipocytes. In light of these microarray data, it is reasonable to assume that phloretin may be beneficial for reducing insulin resistance, in a similar way to the thiazolidinedione class of antidiabetic drugs. (c) 2010 Elsevier Inc. All rights reserved.

Aspartame downregulates 3T3-L1 differentiation.

PubMed

Pandurangan, Muthuraman; Park, Jeongeun; Kim, Eunjung

2014-10-01

Aspartame is an artificial sweetener used as an alternate for sugar in several foods and beverages. Since aspartame is 200 times sweeter than traditional sugar, it can give the same level of sweetness with less substance, which leads to lower-calorie food intake. There are reports that consumption of aspartame-containing products can help obese people lose weight. However, the potential role of aspartame in obesity is not clear. The present study investigated whether aspartame suppresses 3T3-L1 differentiation, by downregulating phosphorylated peroxisome proliferator-activated receptor γ (p-PPARγ), peroxisome proliferator-activated receptor γ (PPARγ), fatty acid-binding protein 4 (FABP4), CCAAT/enhancer-binding protein α (C/EBPα), and sterol regulatory element-binding protein 1 (SREBP1), which are critical for adipogenesis. The 3T3-L1 adipocytes were cultured and differentiated for 6 d in the absence and presence of 10 μg/ml of aspartame. Aspartame reduced lipid accumulation in differentiated adipocytes as evidenced by Oil Red O staining. qRT-PCR analysis showed that the PPARγ, FABP4, and C/EBPα mRNA expression was significantly reduced in the aspartame-treated adipocytes. Western blot analysis showed that the induction of p-PPARγ, PPARγ, SREBP1, and adipsin was markedly reduced in the aspartame-treated adipocytes. Taken together, these data suggest that aspartame may be a potent substance to alter adipocyte differentiation and control obesity.

SDF7, a group of Scoparia dulcis Linn. derived flavonoid compounds, stimulates glucose uptake and regulates adipocytokines in 3T3-F442a adipocytes.

PubMed

Beh, Joo Ee; Khoo, Li Teng; Latip, Jalifah; Abdullah, Mohd Paud; Alitheen, Noorjahan Baru Mohamed; Adam, Zainah; Ismail, Amin; Hamid, Muhajir

2013-10-28

Adipocytes are major tissues involved in glucose uptake second to skeletal muscle and act as the main adipocytokines mediator that regulates glucose uptake mechanism and cellular differentiation. The objective of this study were to examine the effect of the SDF7, which is a fraction consists of four flavonoid compounds (quercetin: p-coumaric acid: luteolin: apigenin=8: 26: 1: 3) from Scoparia dulcis Linn., on stimulating the downstream components of insulin signalling and the adipocytokines expression on different cellular fractions of 3T3-F442a adipocytes. Morphology and lipid accumulation of differentiated 3T3-F442a adipocytes by 100 nM insulin treated with different concentrations of SDF7 and rosiglitazone were examined followed by the evaluation of glucose uptake activity expressions of insulin signalling downstream components (IRS-1, PI3-kinase, PKB, PKC, TC10 and GLUT4) from four cellular fractions (plasma membrane, cytosol, high density microsome and low density microsome). Next, the expression level of adipocytokines (TNF-α, adiponectin and leptin) and immunoblotting of treated 3T3-F442 adipocytes was determined at 30 min and 480 min. Glucose transporter 4 (GLUT4) translocation of 3T3-F442a adipocytes membrane was also determined. Lastly, mRNA expression of adiponectin and PPAR-γ of 3T3-F442a adipocytes were induced and compared with basal concentration. It was found that SDF7 was able to induce adipocytes differentiation with great extends of morphological changes, lipid synthesis and lipid stimulation in vitro. SDF7 stimulation of glucose transport on 3T3-F442a adipocytes are found to be dose independent, time-dependent and plasma membrane GLUT4 expression-dependent. Moreover, SDF7 are observed to be able to suppress TNF-α and leptin expressions that were mediated by 3T3-F442a adipocytes, while stimulated adiponectin secretion on the cells. There was a significant expression (p<0.01) of protein kinase C and small G protein TC10 on 3T3-F442a adipocytes

Mesenchymal Stem Cell Differentiation into Adipocytes Is Equally Induced by Insulin and Proinsulin In Vitro.

PubMed

Pfützner, Andreas; Schipper, Dorothee; Pansky, Andreas; Kleinfeld, Claudia; Roitzheim, Barbara; Tobiasch, Edda

2017-11-30

In advanced β -cell dysfunction, proinsulin is increasingly replacing insulin as major component of the secretion product. It has been speculated that proinsulin has at least the same adipogenic potency than insulin, leading to an increased tendency of lipid tissue formation in patients with late stage β -cell dysfunction. Mesenchymal stem cells obtained from liposuction material were grown in differentiation media containing insulin (0.01 μmol), proinsulin (0.01 μmol) or insulin+proinsulin (each 0.005 μmol). Cell culture supernatants were taken from these experiments and an untreated control at weeks 1, 2, and 3, and were stored at -80°C until analysis. Cell differentiation was microscopically supervised and adiponectin concentrations were measured as marker for differentiation into mature lipid cells. This experiment was repeated three times. No growth of lipid cells and no change in adiponectin values was observed in the negative control group (after 7/14/12 days: 3.2±0.5/3.3±0.1/4.4±0.5 ng/ml/12 h). A continuous differentiation into mature adipocytes (also confirmed by Red-Oil-staining) and a corresponding increase in adiponectin values was observed in the experiments with insulin (3.6±1.9/5.1±1.4/13.3±1.5 ng/ml/12 h; p<0.05 week 1 vs. week 3) and proinsulin (3.3±1.2/3.5±0.3/12.2±1.2 ng/ml/12 h; p<0.05). Comparable effects were seen with the insulin/proinsulin combination. Proinsulin has the same adipogenic potential than insulin in vitro. Proinsulin has only 10∼20% of the glucose-lowering effect of insulin. It can be speculated that the adipogenic potential of proinsulin may be a large contributor to the increased body weight problems in patients with type 2 diabetes and advanced β -cell dysfunction.

Superantigen activates the gp130 receptor on adipocytes resulting in altered adipocyte metabolism.

PubMed

Banke, Elin; Rödström, Karin; Ekelund, Mikael; Dalla-Riva, Jonathan; Lagerstedt, Jens O; Nilsson, Staffan; Degerman, Eva; Lindkvist-Petersson, Karin; Nilson, Bo

2014-06-01

The bacteria Staphylococcus aureus is part of the normal bacterial flora and produces a repertoire of enterotoxins which can cause food poisoning and toxic shock and might contribute to the pathogenesis of inflammatory diseases. These enterotoxins directly cross-link the T cell receptor with MHC class II, activating large amounts of T cells and are therefore called superantigens. It was recently discovered that the superantigen SEA binds to the cytokine receptor gp130. As obesity and type 2 diabetes are highly associated with inflammation of the adipose tissue and gp130 has been shown to play an important role in adipocytes, we wanted to investigate the effect of SEA on adipocyte signaling and function. Binding of SEA to gp130 was examined using surface plasmon resonance in a cell free system. Effects of SEA on adipocyte signaling, insulin sensitivity and function were studied using western blotting and biological assays for lipolysis, lipogenesis and glucose uptake. We demonstrate that SEA binds to gp130 with a medium affinity. Furthermore, SEA induces phosphorylation of a key downstream target, STAT3, in adipocytes. SEA also inhibits insulin-induced activation of PKB and PKB downstream signaling which was associated with reduced basal and insulin induced glucose uptake, reduced lipogenesis as well as reduced ability of insulin to inhibit lipolysis. SEA inhibits insulin signaling as well as insulin biological responses in adipocytes supporting that bacterial infection might contribute to the development of insulin resistance and type 2 diabetes. Copyright © 2014 Elsevier Inc. All rights reserved.

Artemisia scoparia Enhances Adipocyte Development and Endocrine Function In Vitro and Enhances Insulin Action In Vivo

PubMed Central

Richard, Allison J.; Fuller, Scott; Fedorcenco, Veaceslav; Beyl, Robbie; Burris, Thomas P.; Mynatt, Randall; Ribnicky, David M.; Stephens, Jacqueline M.

2014-01-01

Background Failure of adipocytes to expand during periods of energy excess can result in undesirable metabolic consequences such as ectopic fat accumulation and insulin resistance. Blinded screening studies have indicated that Artemisia scoparia (SCO) extracts can enhance adipocyte differentiation and lipid accumulation in cultured adipocytes. The present study tested the hypothesis that SCO treatment modulates fat cell development and function in vitro and insulin sensitivity in adipose tissue in vivo. Methods In vitro experiments utilized a Gal4-PPARγ ligand binding domain (LBD) fusion protein-luciferase reporter assay to examine PPARγ activation. To investigate the ability of SCO to modulate adipogenesis and mature fat cell function in 3T3-L1 cells, neutral lipid accumulation, gene expression, and protein secretion were measured by Oil Red O staining, qRT-PCR, and immunoblotting, respectively. For the in vivo experiments, diet-induced obese (DIO) C57BL/6J mice were fed a high-fat diet (HFD) or HFD containing 1% w/w SCO for four weeks. Body weight and composition, food intake, and fasting glucose and insulin levels were measured. Phospho-activation and expression of insulin-sensitizing proteins in epididymal adipose tissue (eWAT) were measured by immunoblotting. Results Ethanolic extracts of A. scoparia significantly activated the PPARγ LBD and enhanced lipid accumulation in differentiating 3T3-L1 cells. SCO increased the transcription of several PPARγ target genes in differentiating 3T3-L1 cells and rescued the negative effects of tumor necrosis factor α on production and secretion of adiponectin and monocyte chemoattractant protein-1 in fully differentiated fat cells. DIO mice treated with SCO had elevated adiponectin levels and increased phosphorylation of AMPKα in eWAT when compared to control mice. In SCO-treated mice, these changes were also associated with decreased fasting insulin and glucose levels. Conclusion SCO has metabolically beneficial

Lipid droplets hypertrophy: a crucial determining factor in insulin regulation by adipocytes.

PubMed

Sanjabi, Bahram; Dashty, Monireh; Özcan, Behiye; Akbarkhanzadeh, Vishtaseb; Rahimi, Mehran; Vinciguerra, Manlio; van Rooij, Felix; Al-Lahham, Saad; Sheedfar, Fareeba; van Kooten, Theo G; Spek, C Arnold; Rowshani, Ajda T; van der Want, Johannes; Klaassen, Rene; Sijbrands, Eric; Peppelenbosch, Maikel P; Rezaee, Farhad

2015-03-06

Lipid droplets (LDs) hypertrophy in adipocytes is the main cause of energy metabolic system dysfunction, obesity and its afflictions such as T2D. However, the role of adipocytes in linking energy metabolic disorders with insulin regulation is unknown in humans. Human adipocytes constitutively synthesize and secrete insulin, which is biologically functional. Insulin concentrations and release are fat mass- and LDs-dependent respectively. Fat reduction mediated by bariatric surgery repairs obesity-associated T2D. The expression of genes, like PCSK1 (proinsulin conversion enzyme), GCG (Glucagon), GPLD1, CD38 and NNAT, involved in insulin regulation/release were differentially expressed in pancreas and adipose tissue (AT). INS (insulin) and GCG expression reduced in human AT-T2D as compared to AT-control, but remained unchanged in pancreas in either state. Insulin levels (mRNA/protein) were higher in AT derived from prediabetes BB rats with destructed pancreatic β-cells and controls than pancreas derived from the same rats respectively. Insulin expression in 10 human primary cell types including adipocytes and macrophages is an evidence for extrapancreatic insulin-producing cells. The data suggest a crosstalk between AT and pancreas to fine-tune energy metabolic system or may minimize the metabolic damage during diabetes. This study opens new avenues towards T2D therapy with a great impact on public health.

Lipid droplets hypertrophy: a crucial determining factor in insulin regulation by adipocytes

NASA Astrophysics Data System (ADS)

Sanjabi, Bahram; Dashty, Monireh; Özcan, Behiye; Akbarkhanzadeh, Vishtaseb; Rahimi, Mehran; Vinciguerra, Manlio; van Rooij, Felix; Al-Lahham, Saad; Sheedfar, Fareeba; van Kooten, Theo G.; Spek, C. Arnold; Rowshani, Ajda T.; van der Want, Johannes; Klaassen, Rene; Sijbrands, Eric; Peppelenbosch, Maikel P.; Rezaee, Farhad

2015-03-01

Lipid droplets (LDs) hypertrophy in adipocytes is the main cause of energy metabolic system dysfunction, obesity and its afflictions such as T2D. However, the role of adipocytes in linking energy metabolic disorders with insulin regulation is unknown in humans. Human adipocytes constitutively synthesize and secrete insulin, which is biologically functional. Insulin concentrations and release are fat mass- and LDs-dependent respectively. Fat reduction mediated by bariatric surgery repairs obesity-associated T2D. The expression of genes, like PCSK1 (proinsulin conversion enzyme), GCG (Glucagon), GPLD1, CD38 and NNAT, involved in insulin regulation/release were differentially expressed in pancreas and adipose tissue (AT). INS (insulin) and GCG expression reduced in human AT-T2D as compared to AT-control, but remained unchanged in pancreas in either state. Insulin levels (mRNA/protein) were higher in AT derived from prediabetes BB rats with destructed pancreatic β-cells and controls than pancreas derived from the same rats respectively. Insulin expression in 10 human primary cell types including adipocytes and macrophages is an evidence for extrapancreatic insulin-producing cells. The data suggest a crosstalk between AT and pancreas to fine-tune energy metabolic system or may minimize the metabolic damage during diabetes. This study opens new avenues towards T2D therapy with a great impact on public health.

Transdifferentiation of adipocytes to osteoblasts: potential for orthopaedic treatment.

PubMed

Lin, Daphne P L; Dass, Crispin R

2018-03-01

As both adipocytes and osteoblasts originate from the same pool of mesenchymal stem cells, increasing clinical evidence has emerged of the plasticity between the two lineages. For instance, the downregulation of osteoblast differentiation and upregulation of adipogenesis are common features of conditions such as multiple myeloma, obesity and drug-induced bone loss in diabetes mellitus. However, despite in-vitro and in-vivo observations of adipocyte transdifferentiation into osteoblasts, little is known of the underlying mechanisms. This review summarises the current knowledge of this particular transdifferentiation process whereby the Wnt/β-catenin signalling pathway and Runx2 overexpression have been postulated to play a critical role. Furthermore, due to the possibility of a novel therapy in the treatment of bone conditions, a number of agents with the potential to induce adipo-to-osteoblast transdifferentiation have been investigated such as all-trans retinoic acid, bone morphogenetic protein-9 and vascular endothelial growth factor. © 2018 Royal Pharmaceutical Society.

Trans-anethole ameliorates obesity via induction of browning in white adipocytes and activation of brown adipocytes.

PubMed

Kang, Nam Hyeon; Mukherjee, Sulagna; Min, Taesun; Kang, Sun Chul; Yun, Jong Won

2018-05-24

To treat obesity, suppression of white adipose tissue (WAT) expansion and activation of brown adipose tissue (BAT) are considered as potential therapeutic targets. Recent advances have been made in the induction of brown fat-like adipocytes (beige) in WAT, which represents an attractive potential strategy for the management and treatment of obesity. Use of natural compounds for browning of white adipocytes can be considered as a safe and novel strategy against obesity. Here, we report that trans-anethole (TA), a flavoring substance present in the essential oils of various plants, alleviated high fat diet (HFD)-induced obesity in mice models via elevation of the expression of beige-specific genes such as Ppargc1α, Prdm16, Ucp1, Cd137, Cited1, Tbx1, and Trem26. TA also regulated lipid metabolism in white adipocytes via reduction of adipogenesis and lipogenesis as well as elevation of lipolysis and fat oxidation. Moreover, TA exhibited thermogenic activity by increasing mitochondrial biogenesis in white adipocytes and activating brown adipocytes. In addition, molecular docking analysis enabled us to successfully predict core proteins for fat browning such as β3-adrenergic receptor (β3-AR) and sirtuin1 (SIRT1) based on their low binding energy interactions with TA for promotion of regulatory mechanisms. Indeed, agonistic and antagonistic studies demonstrated that TA induced browning of 3T3-L1 adipocytes through activation of β3-AR as well as the AMPK-mediated SIRT1 pathway regulating PPARα and PGC-1α. In conclusion, TA possesses potential therapeutic implications for treatment of obesity by playing multiple modulatory roles in the induction of white fat browning, activation of brown adipocytes, and promotion of lipid catabolism. Copyright © 2018. Published by Elsevier B.V.

Enhancement of Glucose Uptake by Meso-Dihydroguaiaretic Acid through GLUT4 Up-Regulation in 3T3-L1 Adipocytes.

PubMed

Lee, Anna; Choi, Kyeong-Mi; Jung, Won-Beom; Jeong, Heejin; Kim, Ga-Yeong; Lee, Ju Hyun; Lee, Mi Kyeong; Hong, Jin Tae; Roh, Yoon-Seok; Sung, Sang-Hyun; Yoo, Hwan-Soo

2017-08-28

Type 2 diabetes is characterized by insulin resistance, which leads to increased blood glucose levels. Adipocytes are involved in the development of insulin resistance, resulting from the dysfunction of the insulin signaling pathway. In this study, we investigated whether meso -dihydroguaiaretic acid (MDGA) may modulate glucose uptake in adipocytes, and examined its mechanism of action. MDGA enhanced adipogenesis through up-regulation of peroxisome proliferator-activated receptor γ and CCAAT/enhancer-binding protein α in 3T3-L1 adipocytes partially differentiated with sub-optimal concentrations of insulin. MDGA also increased glucose uptake by stimulating expression and translocation of glucose transporter 4 (GLUT4) in adipocytes. These results suggest that MDGA may increase GLUT4 expression and its translocation by promoting insulin sensitivity, leading to enhanced glucose uptake.

Rosmarinic acid suppresses adipogenesis, lipolysis in 3T3-L1 adipocytes, lipopolysaccharide-stimulated tumor necrosis factor-α secretion in macrophages, and inflammatory mediators in 3T3-L1 adipocytes

PubMed Central

Rui, Yehua; Tong, Lingxia; Cheng, Jinbo; Wang, Guiping; Qin, Liqiang; Wan, Zhongxiao

2017-01-01

ABSTRACT Background: Rosmarinic acid (RA) is a natural phenol carboxylic acid with many promising biological effects. It may be a suitable candidate for improving obesity-related adipose tissue dysfunction. Objective: We aimed to investigate the therapeutic use of RA as an anti-obesity agent by measuring its effects on adipogenesis, lipolysis, and messenger RNA (mRNA) expression of major adipokines in 3T3-L1 adipocytes; and its effects on lipopolysaccharide (LPS)-induced tumor necrosis factor-α (TNF-α) secretion in macrophages and inflammatory mediators in 3T3-L1 adipocytes incubated with macrophage-conditioned medium (MCM). Methods: 3T3-L1 preadipocytes were used to explore how RA affects adipogenesis, as well as the involvement of phosphorylated extracellular signal-regulated kinase-1/2 (p-ERK1/2) and mothers against decapentaplegic homolog 3 (p-Smad3). 3T3-L1 preadipocytes were also differentiated into mature adipocytes to explore how RA affects basal and isoproterenol- and forskolin-stimulated lipolysis; and how RA affects key adipokines’ mRNA expression. RAW 264.7 macrophages were stimulated with LPS in the absence or presence of RA to explore RA’s effects on TNF-α secretion. MCM was collected and 3T3-L1 adipocytes were incubated with MCM to explore RA’s effects on interleukin-6 (IL-6), IL-1β, monocyte chemoattractant protein-1 (MCP-1), and RANTES mRNA expression. Results: During the preadipocyte differentiation process, RA suppressed peroxisome proliferator-activated receptor-γ and CCAAT/enhancer binding protein-α, and activated p-ERK1/2 and p-Smad3; inhibition of adipogenesis by RA was partially restored following treatment with p-ERK1/2 and p-Smad3 inhibitors. In mature adipocytes, RA inhibited basal lipolysis; phosphodiesterase-3 inhibitor reversed this. RA also inhibited isoproterenol- and forskolin-stimulated glycerol and free fatty acid release, and the phosphorylation of hormone-sensitive lipase and perilipin. RA had no effects on leptin

Dynamics of Adipocyte Turnover in Humans

DOE Office of Scientific and Technical Information (OSTI.GOV)

Spalding, K; Arner, E; Westermark, P

2007-07-16

Obesity is increasing in an epidemic fashion in most countries and constitutes a public health problem by enhancing the risk for cardiovascular disease and metabolic disorders such as type 2 diabetes. Owing to the increase in obesity, life expectancy may start to decrease in developed countries for the first time in recent history. The factors determining fat mass in adult humans are not fully understood, but increased lipid storage in already developed fat cells is thought to be most important. We show that adipocyte number is a major determinant for the fat mass in adults. However, the number of fatmore » cells stays constant in adulthood in lean and obese and even under extreme conditions, indicating that the number of adipocytes is set during childhood and adolescence. To establish the dynamics within the stable population of adipocytes in adults, we have measured adipocyte turnover by analyzing the integration of {sup 14}C derived from nuclear bomb tests in genomic DNA. Approximately 10% of fat cells are renewed annually at all adult ages and levels of body mass index. Neither adipocyte death nor generation rate is altered in obesity, suggesting a tight regulation of fat cell number that is independent of metabolic profile in adulthood. The high turnover of adipocytes establishes a new therapeutic target for pharmacological intervention in obesity.« less

Insulin and chromium picolinate induce translocation of CD36 to the plasma membrane through different signaling pathways in 3T3-L1 adipocytes, and with a differential functionality of the CD36.

PubMed

Wang, Yiqun; Van Oort, Masja M; Yao, Minghui; Van der Horst, Dick J; Rodenburg, Kees W

2011-09-01

Chromium picolinate (CrPic) has been indicated to activate glucose transporter 4 (GLUT4) trafficking to the plasma membrane (PM) to enhance glucose uptake in 3T3-L1 adipocytes. In skeletal and heart muscle cells, insulin directs the intracellular trafficking of the fatty acid translocase/CD36 to induce the uptake of cellular long-chain fatty acid (LCFA). The current study describes the effects of CrPic and insulin on the translocation of CD36 from intracellular storage pools to the PM in 3T3-L1 adipocytes in comparison with that of GLUT4. Immunofluorescence microscopy and immunoblotting revealed that both CD36 and GLUT4 were expressed and primarily located intracellularly in 3T3-L1 adipocytes. Upon insulin or CrPic stimulation, PM expression of CD36 increased in a similar manner as that for GLUT4; the CrPic-stimulated PM expression was less strong than that of insulin. The increase in PM localization for these two proteins by insulin paralleled LCFA ([1-(14)C]palmitate) or [(3)H]deoxyglucose uptake in 3T3-L1 adipocytes. The induction of the PM expression of GLUT4, but not CD36, or substrate uptake by insulin and CrPic appears to be additive in adipocytes. Furthermore, wortmannin completely inhibited the insulin-stimulated translocation of GLUT4 or CD36 and prevented the increased uptake of glucose or LCFA in these cells. Taken together, for the first time, these findings suggest that both insulin and CrPic induce CD36 translocation to the PM in 3T3-L1 adipocytes and that their translocation-inducing effects are not additive. The signaling pathway inducing the translocations is different, apparently resulting in a differential activity of CD36.

Adipocyte-specific deficiency of NADPH oxidase 4 delays the onset of insulin resistance and attenuates adipose tissue inflammation in obesity

PubMed Central

Den Hartigh, Laura J.; Omer, Mohamed; Goodspeed, Leela; Wang, Shari; Wietecha, Tomasz; O’Brien, Kevin D.; Han, Chang Yeop

2017-01-01

Objective Obesity is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) increase in adipose tissue during the development of obesity. We previously showed that in response to excess nutrients like glucose and palmitate, adipocytes generated ROS via NADPH oxidase (NOX) 4, the major adipocyte isoform, instead of using mitochondrial oxidation. However, the role of NOX4-derived ROS in the development of whole body insulin resistance, adipocyte inflammation, and recruitment of macrophages to adipose tissue during the development of obesity is unknown. Approach and Results In this study, control C57BL/6 mice and mice in which NOX4 has been deleted specifically in adipocytes were fed a high fat, high sucrose (HFHS) diet. During the development of obesity in control mice, adipocyte NOX4 and PPP activity were transiently increased. Primary adipocytes differentiated form mice with adipocytes deficient in NOX4 showed resistance against high glucose or palmitate-induced adipocyte inflammation. Mice with adipocytes deficient in NOX4 showed a delayed onset of insulin resistance during the development of obesity, with an initial reduction in adipose tissue inflammation that normalized with prolonged HFHS feeding. Conclusions These findings imply that NOX4-derived ROS may play a role in the onset of insulin resistance and adipose tissue inflammation. As such, therapeutics targeting NOX4-mediated ROS production could be effective in preventing obesity-associated conditions such as insulin resistance. PMID:28062496

Adipocyte-Specific Deficiency of NADPH Oxidase 4 Delays the Onset of Insulin Resistance and Attenuates Adipose Tissue Inflammation in Obesity.

PubMed

Den Hartigh, Laura J; Omer, Mohamed; Goodspeed, Leela; Wang, Shari; Wietecha, Tomasz; O'Brien, Kevin D; Han, Chang Yeop

2017-03-01

Obesity is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) increase in adipose tissue during the development of obesity. We previously showed that in response to excess nutrients like glucose and palmitate, adipocytes generated ROS via NADPH oxidase (NOX) 4, the major adipocyte isoform, instead of using mitochondrial oxidation. However, the role of NOX4-derived ROS in the development of whole body insulin resistance, adipocyte inflammation, and recruitment of macrophages to adipose tissue during the development of obesity is unknown. In this study, control C57BL/6 mice and mice in which NOX4 has been deleted specifically in adipocytes were fed a high-fat, high-sucrose diet. During the development of obesity in control mice, adipocyte NOX4 and pentose phosphate pathway activity were transiently increased. Primary adipocytes differentiated from mice with adipocytes deficient in NOX4 showed resistance against high glucose or palmitate-induced adipocyte inflammation. Mice with adipocytes deficient in NOX4 showed a delayed onset of insulin resistance during the development of obesity, with an initial reduction in adipose tissue inflammation that normalized with prolonged high-fat, high-sucrose feeding. These findings imply that NOX4-derived ROS may play a role in the onset of insulin resistance and adipose tissue inflammation. As such, therapeutics targeting NOX4-mediated ROS production could be effective in preventing obesity-associated conditions, such as insulin resistance. © 2016 American Heart Association, Inc.

Identification of STAT target genes in adipocytes

PubMed Central

Zhao, Peng; Stephens, Jacqueline M.

2013-01-01

Adipocytes play important roles in lipid storage, energy homeostasis and whole body insulin sensitivity. Studies in the last two decades have identified the hormones and cytokines that activate specific STATs in adipocytes in vitro and in vivo. Five of the seven STAT family members are expressed in adipocyte (STATs 1, 3, 5A, 5B and 6). Many transcription factors, including STATs, have been shown to play an important role in adipose tissue development and function. This review will summarize the importance of adipocytes, indicate the cytokines and hormones that utilize the JAK-STAT signaling pathway in fat cells and focus on the identification of STAT target genes in mature adipocytes. To date, specific target genes have been identified for STATs, 1, 5A and 5B, but not for STATs 3 and 6. PMID:24058802

Free lipid and computerized determination of adipocyte size.

PubMed

Svensson, Henrik; Olausson, Daniel; Holmäng, Agneta; Jennische, Eva; Edén, Staffan; Lönn, Malin

2018-06-21

The size distribution of adipocytes in a suspension, after collagenase digestion of adipose tissue, can be determined by computerized image analysis. Free lipid, forming droplets, in such suspensions implicates a bias since droplets present in the images may be identified as adipocytes. This problem is not always adjusted for and some reports state that distinguishing droplets and cells is a considerable problem. In addition, if the droplets originate mainly from rupture of large adipocytes, as often described, this will also bias size analysis. We here confirm that our ordinary manual means of distinguishing droplets and adipocytes in the images ensure correct and rapid identification before exclusion of the droplets. Further, in our suspensions, prepared with focus on gentle handling of tissue and cells, we find no association between the amount of free lipid and mean adipocyte size or proportion of large adipocytes.

Expression, regulation and functional assessment of the 80 amino acid Small Adipocyte Factor 1 (Smaf1) protein in adipocytes.

PubMed

Ren, Gang; Eskandari, Parisa; Wang, Siqian; Smas, Cynthia M

2016-01-15

The gene for Small Adipocyte Factor 1, Smaf1 (also known as adipogenin, ADIG), encodes a ∼600 base transcript that is highly upregulated during 3T3-L1 in vitro adipogenesis and markedly enriched in adipose tissues. Based on the lack of an obvious open reading frame in the Smaf1 transcript, it is not known if the Smaf1 gene is protein coding or non-coding RNA. Using a peptide from a putative open reading frame of Smaf1 as antigen, we generated antibodies for western analysis. Our studies prove that Smaf1 encodes an adipose-enriched protein which in western blot analysis migrates at ∼10 kDa. Rapid induction of Smaf1 protein occurs during in vitro adipogenesis and its expression in 3T3-L1 adipocytes is positively regulated by insulin and glucose. Moreover, siRNA studies reveal that expression of Smaf1 in adipocytes is wholly dependent on PPARγ. On the other hand, use of siRNA for Smaf1 to nearly abolish its protein expression in adipocytes revealed that Smaf1 does not have a major role in adipocyte triglyceride accumulation, lipolysis or insulin-stimulated pAkt induction. However, immunolocalization studies using HA-tagged Smaf1 reveal enrichment at adipocyte lipid droplets. Together our findings show that Smaf1 is a novel small protein endogenous to adipocytes and that Smaf1 expression is closely tied to PPARγ-mediated signals and the adipocyte phenotype. Copyright © 2015 Elsevier Inc. All rights reserved.

Atrial natriuretic peptide regulates lipid mobilization and oxygen consumption in human adipocytes by activating AMPK

DOE Office of Scientific and Technical Information (OSTI.GOV)

Souza, Sandra C.; Chau, Mary D.L.; Yang, Qing

2011-07-08

Highlights: {yields} Treatment of differentiated human adipocytes with atrial natriuretic peptide (ANP) increased lipolysis and oxygen consumption by activating AMP-activated protein kinase (AMPK). {yields} ANP stimulated lipid mobilization by selective activation of the alpha2 subunit of AMPK and increased energy utilization through activation of both the alpha1 and alpha2 subunits of AMPK. {yields} ANP enhanced adipocyte mitochondrial oxidative capacity as evidenced by induction of oxidative mitochondrial genes and increase in oxygen consumption. {yields} Exposure of human adipocytes to fatty acids and (TNF{alpha}) induced insulin resistance and decreased expression of mitochondrial genes which was restored to normal by ANP. -- Abstract:more » Atrial natriuretic peptide (ANP) has been shown to regulate lipid and carbohydrate metabolism providing a possible link between cardiovascular function and metabolism by mediating the switch from carbohydrate to lipid mobilization and oxidation. ANP exerts a potent lipolytic effect via cGMP-dependent protein kinase (cGK)-I mediated-stimulation of AMP-activated protein kinase (AMPK). Activation of the ANP/cGK signaling cascade also promotes muscle mitochondrial biogenesis and fat oxidation. Here we demonstrate that ANP regulates lipid metabolism and oxygen utilization in differentiated human adipocytes by activating the alpha2 subunit of AMPK. ANP treatment increased lipolysis by seven fold and oxygen consumption by two fold, both of which were attenuated by inhibition of AMPK activity. ANP-induced lipolysis was shown to be mediated by the alpha2 subunit of AMPK as introduction of dominant-negative alpha2 subunit of AMPK attenuated ANP effects on lipolysis. ANP-induced activation of AMPK enhanced mitochondrial oxidative capacity as evidenced by a two fold increase in oxygen consumption and induction of mitochondrial genes, including carnitine palmitoyltransferase 1A (CPT1a) by 1.4-fold, cytochrome C (CytC) by 1.3-fold, and

Polymethoxyflavonoids tangeretin and nobiletin increase glucose uptake in murine adipocytes.

PubMed

Onda, Kenji; Horike, Natsumi; Suzuki, Tai-ichi; Hirano, Toshihiko

2013-02-01

Tangeretin and nobiletin are polymethoxyflavonoids that are contained in citrus fruits. Polymethoxyflavonoids are reported to have several biological functions including anti-inflammatory, anti-atherogenic, or anti-diabetic effects. However, whether polymethoxyflavonoids directly affect glucose uptake in tissues is not well understood. In the current study, we investigated whether tangeretin and nobiletin affect glucose uptake in insulin target cells such as adipocytes. We observed that treatment with tangeretin or nobiletin significantly increased the uptake of [(3) H]-deoxyglucose in differentiated 3T3-F442A adipocytes in a concentration-dependent manner. Data showed that phosphatidyl inositol 3 kinase, Akt1/2, and the protein kinase A pathways were involved in the increase in glucose uptake induced by polymethoxyflavonoids. These data suggest that the anti-diabetic action of polymethoxyflavonoids is partly exerted via these signaling pathways in insulin target tissues. Copyright © 2012 John Wiley & Sons, Ltd.

Obesity is associated with depot-specific alterations in adipocyte DNA methylation and gene expression.

PubMed

Sonne, Si Brask; Yadav, Rachita; Yin, Guangliang; Dalgaard, Marlene Danner; Myrmel, Lene Secher; Gupta, Ramneek; Wang, Jun; Madsen, Lise; Kajimura, Shingo; Kristiansen, Karsten

2017-04-03

The present study aimed to identify genes exhibiting concomitant obesity-dependent changes in DNA methylation and gene expression in adipose tissues in the mouse using diet-induced obese (DIO) C57BL/6J and genetically obese ob/ob mice as models. Mature adipocytes were isolated from epididymal and inguinal adipose tissues of ob/ob and DIO C57BL/6J mice. DNA methylation was analyzed by MeDIP-sequencing and gene expression by microarray analysis. The majority of differentially methylated regions (DMRs) were hypomethylated in obese mice. Global methylation of long interspersed elements indicated that hypomethylation did not reflect methyl donor deficiency. In both DIO and ob/ob mice, we observed more obesity-associated methylation changes in epididymal than in inguinal adipocytes. Assignment of DMRs to promoter, exon, intron and intergenic regions demonstrated that DIO-induced changes in DNA methylation in C57BL/6J mice occurred primarily in exons, whereas inguinal adipocytes of ob/ob mice exhibited a higher enrichment of DMRs in promoter regions than in other regions of the genome, suggesting an influence of leptin on DNA methylation in inguinal adipocytes. We observed altered methylation and expression of 9 genes in epididymal adipocytes, including the known obesity-associated genes, Ehd2 and Kctd15, and a novel candidate gene, Irf8, possibly involved in immune type 1/type2 balance. The use of 2 obesity models enabled us to dissociate changes associated with high fat feeding from those associated with obesity per se. This information will be of value in future studies on the mechanisms governing the development of obesity and changes in adipocyte function associated with obesity.

The estrogen-related receptors and the adipocyte.

PubMed

Carnesecchi, Julie; Vanacker, Jean-Marc

2013-08-01

The estrogen-related receptors (ERRα, β, and γ) are orphan members of the nuclear receptor superfamily. ERRα and γ are highly expressed in tissues displaying elevated energy demands and are involved in several aspects of energetic metabolism, which they regulate mostly in association with members of the PGC-1 coactivator family. These activities have mostly been documented in the liver, heart, or skeletal muscle. ERRα and γ are also highly expressed in adipocytes. Their precise roles in this cell type are less documented, although published data indicate that they contribute to cell differentiation as well as functionality. This review describes these activities.

Skin aging: are adipocytes the next target?

PubMed

Kruglikov, Ilja L; Scherer, Philipp E

2016-07-01

Dermal white adipose tissue (dWAT) is increasingly appreciated as a special fat depot. The adipocytes in this depot exert a variety of unique effects on their surrounding cells and can undergo massive phenotypic changes. Significant modulation of dWAT content can be observed both in intrinsically and extrinsically aged skin. Specifically, skin that has been chronically photo-damaged displays a reduction of the dWAT volume, caused by the replacement of adipocytes by fibrotic structures. This is likely to be caused by the recently uncovered process described as "adipocyte-myofibroblast transition" (AMT). In addition, contributions of dermal adipocytes to the skin aging processes are also indirectly supported by spatial correlations between the prevalence of hypertrophic scarring and the appearance of signs of skin aging in different ethnic groups. These observations could elevate dermal adipocytes to prime targets in strategies aimed at counteracting skin aging.

Skin aging: are adipocytes the next target?

PubMed Central

Kruglikov, Ilja L.; Scherer, Philipp E.

2016-01-01

Dermal white adipose tissue (dWAT) is increasingly appreciated as a special fat depot. The adipocytes in this depot exert a variety of unique effects on their surrounding cells and can undergo massive phenotypic changes. Significant modulation of dWAT content can be observed both in intrinsically and extrinsically aged skin. Specifically, skin that has been chronically photo-damaged displays a reduction of the dWAT volume, caused by the replacement of adipocytes by fibrotic structures. This is likely to be caused by the recently uncovered process described as “adipocyte-myofibroblast transition” (AMT). In addition, contributions of dermal adipocytes to the skin aging processes are also indirectly supported by spatial correlations between the prevalence of hypertrophic scarring and the appearance of signs of skin aging in different ethnic groups. These observations could elevate dermal adipocytes to prime targets in strategies aimed at counteracting skin aging. PMID:27434510

Adenovirus-mediated interference of FABP4 regulates mRNA expression of ADIPOQ, LEP and LEPR in bovine adipocytes.

PubMed

Wei, S; Zan, L S; Wang, H B; Cheng, G; Du, M; Jiang, Z; Hausman, G J; McFarland, D C; Dodson, M V

2013-02-27

Fatty acid binding protein 4 (FABP4) is an important adipocyte gene, with roles in fatty acid transport and fat deposition in animals as well as human metabolic syndrome. However, little is known about the functional regulation of FABP4 at the cellular level in bovine. We designed and selected an effective shRNA (small hairpin RNA) against bovine FABP4, constructed a corresponding adenovirus (AD-FABP4), and then detected its influence on mRNA expression of four differentiation-related genes (PPAR(y), CEBPA, CEBPB, and SREBF1) and three lipid metabolism-related genes (ADIPOQ, LEP and LEPR) of adipocytes. The FABP4 mRNA content, derived from bovine adipocytes, decreased by 41% (P < 0.01) after 24 h and 66% (P < 0.01) after 72 h of AD-FABP4 infection. However, lower mRNA content of FABP4 did not significantly alter levels of differentiation-related gene expression at 24 h following AD-FABP4 treatment of bovine-derived preadipocytes (P = 0.54, 0.78, 0.89, and 0.94, respectively). Meanwhile, knocking down (partially silencing) FABP4 significantly decreased ADIPOQ (P < 0.05) and LEP (P < 0.01) gene expression after 24 h of AD-FABP4 treatment, decreased ADIPOQ (P < 0.01) and LEP (P < 0.01) gene expression, but increased LEPR mRNA expression (P < 0.01) after a 72-h treatment of bovine preadipocytes. We conclude that FABP4 plays a role in fat deposition and metabolic syndrome by regulating lipid metabolism-related genes (such as ADIPOQ, LEP and LEPR), without affecting the ability of preadipocytes to differentiate into adipocytes.

Adipocytes Impair Efficacy of Antiretroviral Therapy

PubMed Central

Couturier, Jacob; Winchester, Lee C.; Suliburk, James W.; Wilkerson, Gregory K.; Podany, Anthony T.; Agarwal, Neeti; Chua, Corrine Ying Xuan; Nehete, Pramod N.; Nehete, Bharti P.; Grattoni, Alessandro; Sastry, K. Jagannadha; Fletcher, Courtney V.; Lake, Jordan E.; Balasubramanyan, Ashok; Lewis, Dorothy E.

2018-01-01

Adequate distribution of antiretroviral drugs to infected cells in HIV patients is critical for viral suppression. In humans and primates, HIV- and SIV-infected CD4 T cells in adipose tissues have recently been identified as reservoirs for infectious virus. To better characterize adipose tissue as a pharmacological sanctuary for HIV-infected cells, in vitro experiments were conducted to assess antiretroviral drug efficacy in the presence of adipocytes, and drug penetration in adipose tissue cells (stromal-vascular-fraction cells and mature adipocytes) was examined in treated humans and monkeys. Co-culture experiments between HIV-1-infected CD4 T cells and primary human adipocytes showed that adipocytes consistently reduced the antiviral efficacy of the nucleotide reverse transcriptase inhibitor tenofovir and its prodrug forms tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). In HIV-infected persons, LC-MS/MS analysis of intracellular lysates derived from adipose tissue stromal-vascular-fraction cells or mature adipocytes suggested that integrase inhibitors penetrate adipose tissue, whereas penetration of nucleoside/nucleotide reverse transcriptase inhibitors such as TDF, emtricitabine, abacavir, and lamivudine is restricted. The limited distribution and functions of key antiretroviral drugs within fat depots may contribute to viral persistence in adipose tissue. PMID:29630975

Sulforaphane inhibits mitotic clonal expansion during adipogenesis through cell cycle arrest.

PubMed

Choi, Kyeong-Mi; Lee, Youn-Sun; Sin, Dong-Mi; Lee, Seunghyun; Lee, Mi Kyeong; Lee, Yong-Moon; Hong, Jin-Tae; Yun, Yeo-Pyo; Yoo, Hwan-Soo

2012-07-01

Obesity is a risk factor for numerous metabolic disorders such as type 2 diabetes, hypertension, and coronary heart disease. Adipocyte differentiation is triggered by adipocyte hyperplasia, which leads to obesity. In this study, the inhibitory effect of sulforaphane, an isothiocyanate, on adipogenesis in 3T3-L1 cells was investigated. Sulforaphane decreased the accumulation of lipid droplets stained with Oil Red O and inhibited the elevation of triglycerides in the adipocytes (half-maximal inhibitory concentration = 7.3 µmol/l). The expression of peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), major transcription factors for adipocyte differentiation, was significantly reduced by sulforaphane. The major effects of sulforaphane on the inhibition of adipocyte differentiation occurred during the early stage of adipogenesis. Thus, the expression of C/EBPβ, an early-stage biomarker of adipogenesis, decreased in a concentration-dependent manner when the adipocytes were exposed to sulforaphane (0, 5, 10, and 20 µmol/l). The proliferation of adipocytes treated with 20 µmol/l sulforaphane for 24 and 48 h was also suppressed. These results indicate that sulforaphane may specifically affect mitotic clonal expansion to inhibit adipocyte differentiation. Sulforaphane arrested the cell cycle at the G(0)/G(1) phase, increased p27 expression, and decreased retinoblastoma (Rb) phosphorylation. Additionally, sulforaphane modestly decreased the phosphorylation of ERK1/2 and Akt. Our results indicate that the inhibition of early-stage adipocyte differentiation by sulforaphane may be associated with cell cycle arrest at the G(0)/G(1) phase through upregulation of p27 expression.

The differentiation of preadipocytes and gene expression related to adipogenesis in ducks (Anas platyrhynchos).

PubMed

Wang, Shasha; Zhang, Yang; Xu, Qi; Yuan, Xiaoya; Dai, Wangcheng; Shen, Xiaokun; Wang, Zhixiu; Chang, Guobin; Wang, Zhiquan; Chen, Guohong

2018-01-01

Meat quality is closely related to adipose tissues in ducks, and adipogenesis is controlled by a complex network of transcription factors tightly acting at different stages of differentiation especially in ducks. The aim of this study was to establish the preadipocyte in vitro culture system and understand the biological characteristics of expansion of duck adipocyte tissue at the cellular and molecular level. We isolated pre-adipocytes from the subcutaneous fat of three breeds of duck and differentiated them into mature adipocytes using a mixture of insulin, rosiglitazone, dexamethasone, 3-isobutyl-1-methylxanthine, and oleic acid over 0,2, 4, 6, and 8 days. Successful differentiation was confirmed from the development of lipid droplets and their response to Oil Red O, and increasing numbers of lipid droplets were stained red over time. The expression of key marker genes, including peroxisome proliferator activated receptor γ (PPARγ), CCAAT/enhancer binding protein-α (C/EBPα), adipocyte fatty acid binding protein 4 (FABP4), and fatty acid synthetase (FAS), gradually increased during pre-adipocyte differentiation. Furthermore, it was verified by interference experiments that the knockdown of PPARγ directly reduced lipid production. Meanwhile we analyzed the role of unsaturated fatty acids in the production of poultry fat using different concentrations of oleic acid and found that lipid droplet deposition was highest when the concentration of oleic acid was 300 μM. We also compared the level of differentiated pre-adipocytes that were isolated from Jianchang ducks (fatty-meat duck), Cherry Valley ducks (lean-meat duck) and White-crested ducks (egg-producing duck). The proliferation and differentiation rate of pre-adipocytes derived from Jianchang ducks was higher than that of White-crested ducks. These results provide the foundation for further research into waterfowl adipogenesis.

Dietary Quercetin Attenuates Adipose Tissue Expansion and Inflammation and Alters Adipocyte Morphology in a Tissue-Specific Manner

PubMed Central

Forney, Laura A.; Lenard, Natalie R.; Stewart, Laura K.

2018-01-01

Chronic inflammation in adipose tissue may contribute to depot-specific adipose tissue expansion, leading to obesity and insulin resistance. Dietary supplementation with quercetin or botanical extracts containing quercetin attenuates high fat diet (HFD)-induced obesity and insulin resistance and decreases inflammation. Here, we determined the effects of quercetin and red onion extract (ROE) containing quercetin on subcutaneous (inguinal, IWAT) vs. visceral (epididymal, EWAT) white adipose tissue morphology and inflammation in mice fed low fat, high fat, high fat plus 50 μg/day quercetin or high fat plus ROE containing 50 μg/day quercetin equivalents for 9 weeks. Quercetin and ROE similarly ameliorated HFD-induced increases in adipocyte size and decreases in adipocyte number in IWAT and EWAT. Furthermore, quercetin and ROE induced alterations in adipocyte morphology in IWAT. Quercetin and ROE similarly decreased HFD-induced IWAT inflammation. However, quercetin and red onion differentially affected HFD-induced EWAT inflammation, with quercetin decreasing and REO increasing inflammatory marker gene expression. Quercetin and REO also differentially regulated circulating adipokine levels. These results show that quercetin or botanical extracts containing quercetin induce white adipose tissue remodeling which may occur through inflammatory-related mechanisms. PMID:29562620

A possible regulatory link between Twist 1 and PPARγ gene regulation in 3T3-L1 adipocytes.

PubMed

Ren, Rui; Chen, Zhufeng; Zhao, Xia; Sun, Tao; Zhang, Yuchao; Chen, Jie; Lu, Sumei; Ma, Wanshan

2016-11-08

Peroxisome proliferator-activated receptor γ (PPARγ) is a critical gene that regulates the function of adipocytes. Therefore, studies on the molecular regulation mechanism of PPARγ are important to understand the function of adipose tissue. Twist 1 is another important functional gene in adipose tissue, and hundreds of genes are regulated by Twist 1. The aim of this study was to investigate the regulation of Twist 1 and PPARγ expression in 3T3-L1 mature adipocytes. We induced differentiation in 3T3-L1 preadipocytes and examined alterations in Twist 1 and PPARγ expression. We used the PPARγ agonist pioglitazone and the PPARγ antagonist T0070907 to investigate the effect of PPARγ on Twist 1 expression. In addition, we utilized retroviral interference and overexpression of Twist 1 to determine the effects of Twist 1 on PPARγ expression. The expression levels of Twist 1 and PPARγ were induced during differentiation in 3T3-L1 adipocytes. Application of either a PPARγ agonist (pioglitazone) or antagonist (T0070907) influenced Twist 1 expression, with up-regulation of Twist 1 under pioglitazone (1 μM, 24 h) and down-regulation of Twist 1 under T0070907 (100 μM, 24 h) exposure. Furthermore, the retroviral interference of Twist 1 decreased the protein and mRNA expression of PPARγ, while Twist 1 overexpression had the opposite effect. There was a possible regulatory link between Twist 1 and PPARγ in 3T3-L1 mature adipocytes. This regulatory link enhanced the regulation of PPARγ and may be a functional mechanism of Twist 1 regulation of adipocyte physiology and pathology.

Palmitoleic acid (16:1n7) increases oxygen consumption, fatty acid oxidation and ATP content in white adipocytes.

PubMed

Cruz, Maysa M; Lopes, Andressa B; Crisma, Amanda R; de Sá, Roberta C C; Kuwabara, Wilson M T; Curi, Rui; de Andrade, Paula B M; Alonso-Vale, Maria I C

2018-03-20

We have recently demonstrated that palmitoleic acid (16:1n7) increases lipolysis, glucose uptake and glucose utilization for energy production in white adipose cells. In the present study, we tested the hypothesis that palmitoleic acid modulates bioenergetic activity in white adipocytes. For this, 3 T3-L1 pre-adipocytes were differentiated into mature adipocytes in the presence (or absence) of palmitic (16:0) or palmitoleic (16:1n7) acid at 100 or 200 μM. The following parameters were evaluated: lipolysis, lipogenesis, fatty acid (FA) oxidation, ATP content, oxygen consumption, mitochondrial mass, citrate synthase activity and protein content of mitochondrial oxidative phosphorylation (OXPHOS) complexes. Treatment with 16:1n7 during 9 days raised basal and isoproterenol-stimulated lipolysis, FA incorporation into triacylglycerol (TAG), FA oxidation, oxygen consumption, protein expression of subunits representing OXPHOS complex II, III, and V and intracellular ATP content. These effects were not observed in adipocytes treated with 16:0. Palmitoleic acid, by concerted action on lipolysis, FA esterification, mitochondrial FA oxidation, oxygen consumption and ATP content, does enhance white adipocyte energy expenditure and may act as local hormone.

Influence of epidermal growth factor (EGF) and hydrocortisone on the co-culture of mature adipocytes and endothelial cells for vascularized adipose tissue engineering.

PubMed

Huber, Birgit; Czaja, Alina Maria; Kluger, Petra Juliane

2016-05-01

The composition of vascularized adipose tissue is still an ongoing challenge as no culture medium is available to supply adipocytes and endothelial cells appropriately. Endothelial cell medium is typically supplemented with epidermal growth factor (EGF) as well as hydrocortisone (HC). The effect of EGF on adipocytes is discussed controversially. Some studies say it inhibits adipocyte differentiation while others reported of improved adipocyte lipogenesis. HC is known to have lipolytic activities, which might result in mature adipocyte dedifferentiation. In this study, we evaluated the influence of EGF and HC on the co-culture of endothelial cells and mature adipocytes regarding their cell morphology and functionality. We showed in mono-culture that high levels of HC promoted dedifferentiation and proliferation of mature adipocytes, whereas EGF seemed to have no negative influence. Endothelial cells kept their typical cobblestone morphology and showed a proliferation rate comparable to the control independent of EGF and HC concentration. In co-culture, HC promoted dedifferentiation of mature adipocytes, which was shown by a higher glycerol release. EGF had no negative impact on adipocyte morphology. No negative impact on endothelial cell morphology and functionality could be seen with reduced EGF and HC supplementation in co-culture with mature adipocytes. Taken together, our results demonstrate that reduced levels of HC are needed for co-culturing mature adipocytes and endothelial cells. In co-culture, EGF had no influence on mature adipocytes. Therefore, for the composition of vascularized adipose tissue constructs, the media with low levels of HC and high or low levels of EGF can be used. © 2016 International Federation for Cell Biology.

Adipocyte differentiation-related protein promotes lipid accumulation in goat mammary epithelial cells.

PubMed

Shi, H B; Yu, K; Luo, J; Li, J; Tian, H B; Zhu, J J; Sun, Y T; Yao, D W; Xu, H F; Shi, H P; Loor, J J

2015-10-01

Milk fat originates from the secretion of cytosolic lipid droplets (CLD) synthesized within mammary epithelial cells. Adipocyte differentiation-related protein (ADRP; gene symbol PLIN2) is a CLD-binding protein that is crucial for synthesis of mature CLD. Our hypothesis was that ADRP regulates CLD production and metabolism in goat mammary epithelial cells (GMEC) and thus plays a role in determining milk fat content. To understand the role of ADRP in ruminant milk fat metabolism, ADRP (PLIN2) was overexpressed or knocked down in GMEC using an adenovirus system. Immunocytochemical staining revealed that ADRP localized to the surface of CLD. Supplementation with oleic acid (OA) enhanced its colocalization with CLD surface and enhanced lipid accumulation. Overexpression of ADRP increased lipid accumulation and the concentration of triacylglycerol in GMEC. In contrast, morphological examination revealed that knockdown of ADRP decreased lipid accumulation even when OA was supplemented. This response was confirmed by the reduction in mass of cellular TG when ADRP was knocked down. The fact that knockdown of ADRP did not completely eliminate lipid accumulation at a morphological level in GMEC without OA suggests that some other compensatory factors may also aid in the process of CLD formation. The ADRP reversed the decrease of CLD accumulation induced by adipose triglyceride lipase. This is highly suggestive of ADRP promoting triacylglycerol stability within CLD by preventing access to adipose triglyceride lipase. Collectively, these data provide direct in vitro evidence that ADRP plays a key role in CLD formation and stability in GMEC. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Roles of leptin and ghrelin in adipogenesis and lipid metabolism of rainbow trout adipocytes in vitro.

PubMed

Salmerón, Cristina; Johansson, Marcus; Asaad, Maryam; Angotzi, Anna R; Rønnestad, Ivar; Stefansson, Sigurd O; Jönsson, Elisabeth; Björnsson, Björn Thrandur; Gutiérrez, Joaquim; Navarro, Isabel; Capilla, Encarnación

2015-10-01

Leptin and ghrelin are important regulators of energy homeostasis in mammals, whereas their physiological roles in fish have not been fully elucidated. In the present study, the effects of leptin and ghrelin on adipogenesis, lipolysis and on expression of lipid metabolism-related genes were examined in rainbow trout adipocytes in vitro. Leptin expression and release increased from preadipocytes to mature adipocytes in culture, but did not affect the process of adipogenesis. While ghrelin and its receptor were identified in cultured differentiated adipocytes, ghrelin did not influence either preadipocyte proliferation or differentiation, indicating that it may have other adipose-related roles. Leptin and ghrelin increased lipolysis in mature freshly isolated adipocytes, but mRNA expression of lipolysis markers was not significantly modified. Leptin significantly suppressed the fatty acid transporter-1 expression, suggesting a decrease in fatty acid uptake and storage, but did not affect expression of any of the lipogenesis or β-oxidation genes studied. Ghrelin significantly increased the mRNA levels of lipoprotein lipase, fatty acid synthase and peroxisome proliferator-activated receptor-β, and thus appears to stimulate synthesis of triglycerides as well as their mobilization. Overall, the study indicates that ghrelin, but not leptin seems to be an enhancer of lipid turn-over in adipose tissue of rainbow trout, and this regulation may at least partly be mediated through autocrine/paracrine mechanisms. The mode of action of both hormones needs to be further explored to better understand their roles in regulating adiposity in fish. Copyright © 2015 Elsevier Inc. All rights reserved.

Integrator complex plays an essential role in adipose differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Otani, Yuichiro; Nakatsu, Yusuke; Sakoda, Hideyuki

2013-05-03

Highlights: •IntS6 and IntS11 are subunits of the Integrator complex. •Expression levels of IntS6 and IntS11 were very low in 3T3-L1 fibroblast. •IntS6 and IntS11 were upregulated during adipose differentiation. •Suppression of IntS6 or IntS11 expression inhibited adipose differentiation. -- Abstract: The dynamic process of adipose differentiation involves stepwise expressions of transcription factors and proteins specific to the mature fat cell phenotype. In this study, it was revealed that expression levels of IntS6 and IntS11, subunits of the Integrator complex, were increased in 3T3-L1 cells in the period when the cells reached confluence and differentiated into adipocytes, while being reducedmore » to basal levels after the completion of differentiation. Suppression of IntS6 or IntS11 expression using siRNAs in 3T3-L1 preadipocytes markedly inhibited differentiation into mature adipocytes, based on morphological findings as well as mRNA analysis of adipocyte-specific genes such as Glut4, perilipin and Fabp4. Although Pparγ2 protein expression was suppressed in IntS6 or IntS11-siRNA treated cells, adenoviral forced expression of Pparγ2 failed to restore the capacity for differentiation into mature adipocytes. Taken together, these findings demonstrate that increased expression of Integrator complex subunits is an indispensable event in adipose differentiation. Although further study is necessary to elucidate the underlying mechanism, the processing of U1, U2 small nuclear RNAs may be involved in cell differentiation steps.« less

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Ping, E-mail: lping@sdu.edu.cn; Kong, Feng; Wang, Jue

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0–G1 phase cells, and promoted apoptosis. During PVACmore » proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. - Highlights: • IGF-1 activated PI3K/Akt2 and ERK1/2 pathways to mediate PVAC proliferation and differentiation. • The expression of ERK1, ERK 2, PI3K, Akt1 and Akt2 showed different change trends between PVAC proliferation and differentiation. • MEOX2 effectively expressed in PVAC, increased early and late cellular apoptosis, and inhibited its proliferation. • MEOX2 depressed PVAC differentiation and FAS

Transcriptional activation of melanocortin 2 receptor accessory protein by PPARγ in adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Nam Soo; Kim, Yoon-Jin; Cho, Si Young

2013-09-27

Highlights: •MRAP enhanced HSL expression. •ACTH-mediated MRAP reduced glycerol release. •PPARγ induced MRAP expression. •PPARγ bound to the MRAP promoter. -- Abstract: Adrenocorticotropic hormone (ACTH) in rodents decreases lipid accumulation and body weight. Melanocortin receptor 2 (MC2R) and MC2R accessory protein (MRAP) are specific receptors for ACTH in adipocytes. Peroxisome proliferator-activated receptor γ (PPARγ) plays a role in the transcriptional regulation of metabolic pathways such as adipogenesis and β-oxidation of fatty acids. In this study we investigated the transcriptional regulation of MRAP expression during differentiation of 3T3-L1 cells. Stimulation with ACTH affected lipolysis in murine mature adipocytes via MRAP. Putativemore » peroxisome proliferator response element (PPRE) was identified in the MRAP promoter region. In chromatin immunoprecipitation and reporter assays, we observed binding of PPARγ to the MRAP promoter. The mutagenesis experiments showed that the −1209/−1198 region of the MRAP promoter could function as a PPRE site. These results suggest that PPARγ is required for transcriptional activation of the MRAP gene during adipogenesis, which contributes to understanding of the molecular mechanism of lipolysis in adipocytes.« less

L-rhamnose induces browning in 3T3-L1 white adipocytes and activates HIB1B brown adipocytes.

PubMed

Choi, Minji; Mukherjee, Sulagna; Kang, Nam Hyeon; Barkat, Jameel Lone; Parray, Hilal Ahmad; Yun, Jong Won

2018-06-01

Induction of the brown adipocyte-like phenotype in white adipocytes (browning) is considered as a novel strategy to fight obesity due to the ability of brown adipocytes to increase energy expenditure. Here, we report that L-rhamnose induced browning by elevating expression levels of beige-specific marker genes, including Cd137, Cited1, Tbx1, Prdm16, Tmem26, and Ucp1, in 3T3-L1 adipocytes. Moreover, L-rhamnose markedly elevated expression levels of proteins involved in thermogenesis both in 3T3-L1 white and HIB1B brown adipocytes. L-rhamnose treatment in 3T3-L1 adipocytes also significantly elevated protein levels of p-HSL, p-AMPK, ACOX, and CPT1 as well as reduced levels of ACC, FAS, C/EBPα, and PPARγ, suggesting its possible role in enhancement of lipolysis and lipid catabolism as well as reduced adipogenesis and lipogenesis, respectively. The quick technique of efficient molecular docking provided insight into the strong binding of L-rhamnose to the fat-digesting glycine residue of β 3 -adrenergic receptor (AR), indicating strong involvement of L-rhamnose in fat metabolism. Further examination of the molecular mechanism of L-rhamnose revealed that it induced browning of 3T3-L1 adipocytes via coordination of multiple signaling pathways through β 3 -AR, SIRT1, PKA, and p-38. To the best of our knowledge, this is the first study to demonstrate that L-rhamnose plays multiple modulatory roles in the induction of white fat browning, activation of brown adipocytes, as well as promotion of lipid metabolism, thereby demonstrating its therapeutic potential for treatment of obesity. © 2018 IUBMB Life, 70(6):563-573, 2018. © 2018 International Union of Biochemistry and Molecular Biology.

Adipocyte Origins: Weighing the Possibilities

PubMed Central

Majka, Susan M.; Barak, Yaacov; Klemm, Dwight J.

2012-01-01

Adipose tissue is the primary energy reservoir in the body and an important endocrine organ that plays roles in energy homeostasis, feeding, insulin sensitivity and inflammation. While it was tacitly assumed that fat in different anatomical locations had a common origin and homogenous function, it is now clear that regional differences exist in adipose tissue characteristics and function. This is exemplified by the link between increased deep abdominal or visceral fat, but not peripheral adipose tissue, and the metabolic disturbances associated with obesity. Regional differences in fat function are due in large part to distinct adipocyte populations that comprise the different fat depots. Evidence accrued primarily in the last decade indicate that the distinct adipocyte populations are generated by a number of processes during and after development. These include the production of adipocytes from different germ cell layers, the formation of distinct preadipocyte populations from mesenchymal progenitors of mesodermal origin, and the production of adipocytes from hematopoietic stem cells from the bone marrow. This review will examine each of these process and their relevance to normal adipose tissue formation and contribution to obesity-related diseases. PMID:21544899

Adipocytes impair efficacy of antiretroviral therapy.

PubMed

Couturier, Jacob; Winchester, Lee C; Suliburk, James W; Wilkerson, Gregory K; Podany, Anthony T; Agarwal, Neeti; Xuan Chua, Corrine Ying; Nehete, Pramod N; Nehete, Bharti P; Grattoni, Alessandro; Sastry, K Jagannadha; Fletcher, Courtney V; Lake, Jordan E; Balasubramanyam, Ashok; Lewis, Dorothy E

2018-06-01

Adequate distribution of antiretroviral drugs to infected cells in HIV patients is critical for viral suppression. In humans and primates, HIV- and SIV-infected CD4 T cells in adipose tissues have recently been identified as reservoirs for infectious virus. To better characterize adipose tissue as a pharmacological sanctuary for HIV-infected cells, in vitro experiments were conducted to assess antiretroviral drug efficacy in the presence of adipocytes, and drug penetration in adipose tissue cells (stromal-vascular-fraction cells and mature adipocytes) was examined in treated humans and monkeys. Co-culture experiments between HIV-1-infected CD4 T cells and primary human adipocytes showed that adipocytes consistently reduced the antiviral efficacy of the nucleotide reverse transcriptase inhibitor tenofovir and its prodrug forms tenofovir disoproxil fumarate (TDF) and tenofovir alafenamide (TAF). In HIV-infected persons, LC-MS/MS analysis of intracellular lysates derived from adipose tissue stromal-vascular-fraction cells or mature adipocytes suggested that integrase inhibitors penetrate adipose tissue, whereas penetration of nucleoside/nucleotide reverse transcriptase inhibitors such as TDF, emtricitabine, abacavir, and lamivudine is restricted. The limited distribution and functions of key antiretroviral drugs within fat depots may contribute to viral persistence in adipose tissue. Copyright © 2018 Elsevier B.V. All rights reserved.

Berberine Suppresses Adipocyte Differentiation via Decreasing CREB Transcriptional Activity

PubMed Central

Deng, Ruyuan; Wang, Ning; Zhang, Yuqing; Wang, Yao; Liu, Yun; Li, Fengying; Wang, Xiao; Zhou, Libin

2015-01-01

Berberine, one of the major constituents of Chinese herb Rhizoma coptidis, has been demonstrated to lower blood glucose, blood lipid, and body weight in patients with type 2 diabetes mellitus. The anti-obesity effect of berberine has been attributed to its anti-adipogenic activity. However, the underlying molecular mechanism remains largely unknown. In the present study, we found that berberine significantly suppressed the expressions of CCAAT/enhancer-binding protein (C/EBP)α, peroxisome proliferators-activated receptor γ2 (PPARγ2), and other adipogenic genes in the process of adipogenesis. Berberine decreased cAMP-response element-binding protein (CREB) phosphorylation and C/EBPβ expression at the early stage of 3T3-L1 preadipocyte differentiation. In addition, CREB phosphorylation and C/EBPβ expression induced by 3-isobutyl-1-methylxanthine (IBMX) and forskolin were also attenuated by berberine. The binding activities of cAMP responsive element (CRE) stimulated by IBMX and forskolin were inhibited by berberine. The binding of phosphorylated CREB to the promoter of C/EBPβ was abrogated by berberine after the induction of preadipocyte differentiation. These results suggest that berberine blocks adipogenesis mainly via suppressing CREB activity, which leads to a decrease in C/EBPβ-triggered transcriptional cascades. PMID:25928058

11β-HSD1 reduces metabolic efficacy and adiponectin synthesis in hypertrophic adipocytes.

PubMed

Koh, Eun Hee; Kim, Ah-Ram; Kim, Hyunshik; Kim, Jin Hee; Park, Hye-Sun; Ko, Myoung Seok; Kim, Mi-Ok; Kim, Hyuk-Joong; Kim, Bum Joong; Yoo, Hyun Ju; Kim, Su Jung; Oh, Jin Sun; Woo, Chang-Yun; Jang, Jung Eun; Leem, Jaechan; Cho, Myung Hwan; Lee, Ki-Up

2015-06-01

Mitochondrial dysfunction in hypertrophic adipocytes can reduce adiponectin synthesis. We investigated whether 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) expression is increased in hypertrophic adipocytes and whether this is responsible for mitochondrial dysfunction and reduced adiponectin synthesis. Differentiated 3T3L1 adipocytes were cultured for up to 21 days. The effect of AZD6925, a selective 11β-HSD1 inhibitor, on metabolism was examined. db/db mice were administered 600 mg/kg AZD6925 daily for 4 weeks via gastric lavage. Mitochondrial DNA (mtDNA) content, mRNA expression levels of 11 β -H sd1 and mitochondrial biogenesis factors, adiponectin synthesis, fatty acid oxidation (FAO), oxygen consumption rate and glycolysis were measured. Adipocyte hypertrophy in 3T3L1 cells exposed to a long duration of culture was associated with increased 11 β -Hsd1 mRNA expression and reduced mtDNA content, mitochondrial biogenesis factor expression and adiponectin synthesis. These cells displayed reduced mitochondrial respiration and increased glycolysis. Treatment of these cells with AZD6925 increased adiponectin synthesis and mitochondrial respiration. Inhibition of FAO by etomoxir blocked the AZD6925-induced increase in adiponectin synthesis, indicating that 11β-HSD1-mediated reductions in FAO are responsible for the reduction in adiponectin synthesis. The expression level of 11 β -Hsd1 was higher in adipose tissues of db/db mice. Administration of AZD6925 to db/db mice increased the plasma adiponectin level and adipose tissue FAO. In conclusion, increased 11β-HSD1 expression contributes to reduced mitochondrial respiration and adiponectin synthesis in hypertrophic adipocytes. © 2015 Society for Endocrinology.

Direct and Indirect Effects of Leptin on Adipocyte Metabolism

PubMed Central

Harris, Ruth B.S.

2013-01-01

Leptin is hypothesized to function as a negative feedback signal in the regulation of energy balance. It is produced primarily by adipose tissue and circulating concentrations correlate with the size of body fat stores. Administration of exogenous leptin to normal weight, leptin responsive animals inhibits food intake and reduces the size of body fat stores whereas mice that are deficient in either leptin or functional leptin receptors are hyperphagic and obese, consistent with a role for leptin in the control of body weight. This review discusses the effect of leptin on adipocyte metabolism. Because adipocytes express leptin receptors there is the potential for leptin to influence adipocyte metabolism directly. Adipocytes also are insulin responsive and receive sympathetic innervation, therefore leptin can also modify adipocyte metabolism indirectly. Studies published to date suggest that direct activation of adipocyte leptin receptors has little effect on cell metabolism in vivo, but that leptin modifies adipocyte sensitivity to insulin to inhibit lipid accumulation. In vivo administration of leptin leads to a suppression of lipogenesis, an increase in triglyceride hydrolysis and an increase in fatty acid and glucose oxidation. Activation of central leptin receptors also contributes to the development of a catabolic state in adipocytes, but this may vary between different fat depots. Leptin reduces the size of white fat depots by inhibiting cell proliferation both through induction of inhibitory circulating factors and by contributing to sympathetic tone which suppresses adipocyte proliferation. PMID:23685313

Lithospermum erythrorhizon suppresses high-fat diet-induced obesity, and acetylshikonin, a main compound of Lithospermum erythrorhizon, inhibits adipocyte differentiation.

PubMed

Gwon, So Young; Ahn, Ji Yun; Chung, Chang Hwa; Moon, BoKyung; Ha, Tae Youl

2012-09-12

Lithospermum erythrorhizon, which has traditionally been used as a vegetable and to make the liquor Jindo Hongju, contains several naphthoquinone pigments, including shikonin. This study aimed to evaluate the antiobesity effects of Lithospermum erythrorhizon ethanol extract (LE) and elucidate the underlying mechanism. C57BL/6J mice were fed a normal or high-fat diet with or without LE supplementation for 8 weeks. LE reduced high-fat diet-induced increases in body weight, white adipose tissue mass, serum triglyceride and total cholesterol levels, and hepatic lipid levels while decreasing lipogenic and adipogenic gene expression. Furthermore, acetylshikonin suppressed adipocyte differentiation in a dose-dependent manner and significantly attenuated adipogenic transcription factor expression in 3T3-L1 cells. These findings suggest that Lithospermum erythrorhizon prevents obesity by inhibiting adipogenesis through downregulation of genes involved in the adipogenesis pathway and may be a useful dietary supplement for the prevention of obesity.

Gene expression profile of isolated rat adipocytes treated with anthocyanins.

PubMed

Tsuda, Takanori; Ueno, Yuki; Kojo, Hitoshi; Yoshikawa, Toshikazu; Osawa, Toshihiko

2005-04-15

Adipocyte dysfunction is strongly associated with the development of obesity and insulin resistance. It is accepted that the regulation of adipocytokine secretion or the adipocyte specific gene expression is one of the most important targets for the prevention of obesity and amelioration of insulin sensitivity. Recently, we demonstrated that anthocyanins, which are pigments widespread in the plant kingdom, have the potency of anti-obesity in mice and the enhancement adipocytokine secretion and adipocyte gene expression in adipocytes. In this study, we have shown for the first time the gene expression profile in isolated rat adipocytes treated with anthocyanins (cyanidin 3-glucoside; C3G or cyanidin; Cy). The rat adipocytes were treated with 100 muM C3G, Cy or vehicle for 24 h. The total RNA from the adipocytes was isolated and carried out GeneChip microarray analysis. A total of 633 or 427 genes was up-regulated (>1.5-fold) by the treatment of adipocytes with C3G or Cy, respectively. The up-regulated genes include lipid metabolism and signal transduction-related genes, however, the altered genes were partly different between the C3G- and Cy-treated groups. Based on the gene expression profile, we demonstrated the up-regulation of hormone sensitive lipase and enhancement of the lipolytic activity by the treatment of adipocytes with C3G or Cy. These data have provided an overview of the gene expression profiles in adipocytes treated with anthocyanins and identified new responsive genes with potentially important functions in adipocytes related with obesity and diabetes that merit further investigation.

Zinc-α2-glycoprotein, a lipid mobilizing factor, is expressed in adipocytes and is up-regulated in mice with cancer cachexia

PubMed Central

Bing, Chen; Bao, Yi; Jenkins, John; Sanders, Paul; Manieri, Monia; Cinti, Saverio; Tisdale, Michael J.; Trayhurn, Paul

2004-01-01

Zinc-α2-glycoprotein (ZAG), a 43-kDa protein, is overexpressed in certain human malignant tumors and acts as a lipid-mobilizing factor to stimulate lipolysis in adipocytes leading to cachexia in mice implanted with ZAG-producing tumors. Because white adipose tissue (WAT) is an endocrine organ secreting a wide range of protein factors, including those involved in lipid metabolism, we have investigated whether ZAG is produced locally by adipocytes. ZAG mRNA was detected by RT-PCR in the mouse WAT depots examined (epididymal, perirenal, s.c., and mammary gland) and in interscapular brown fat. In WAT, ZAG gene expression was evident in mature adipocytes and in stromal-vascular cells. Using a ZAG Ab, ZAG protein was located in WAT by Western blotting and immunohistochemistry. Mice bearing the MAC16-tumor displayed substantial losses of body weight and fat mass, which was accompanied by major increases in ZAG mRNA and protein levels in WAT and brown fat. ZAG mRNA was detected in 3T3-L1 cells, before and after the induction of differentiation, with the level increasing progressively after differentiation with a peak at days 8–10. Both dexamethasone and a β3 agonist, BRL 37344, increased ZAG mRNA levels in 3T3-L1 adipocytes. ZAG gene expression and protein were also detected in human adipose tissue (visceral and s.c.). It is suggested that ZAG is a new adipose tissue protein factor, which may be involved in the modulation of lipolysis in adipocytes. Overexpression in WAT of tumor-bearing mice suggests a local role for adipocyte-derived ZAG in the substantial reduction of adiposity of cancer cachexia. PMID:14983038

Honokiol exerts dual effects on browning and apoptosis of adipocytes.

PubMed

Lone, Jameel; Yun, Jong Won

2017-12-01

Induction of brown adipocyte-like phenotype (browning) in white adipocytes and promotion of apoptosis by dietary and pharmacological compounds is considered a novel strategy against obesity. Here, we show that honokiol exerts dual modulatory effects on adipocytes via induction of browning in 3T3-L1 white adipocytes and apoptosis as well as activation of HIB1B brown adipocytes combined with inhibition of apoptosis. Honokiol-induced browning and apoptosis were investigated by determining expression levels of brown adipocyte-specific genes and proteins by RT-PCR and immunoblot analysis, respectively. Apoptotic data were validated by immunofluorescence and ROS levels were measured by FACS analysis. Honokiol treatment induced browning by elevating expression levels of brown adipocyte-specific genes such as Cidea, Cox8, Fgf21, Pgc-1α, and Ucp1. Honokiol promoted apoptosis of 3T3-L1 white adipocytes and inhibited apoptosis of HIB1B brown adipocytes via opposite regulation of the pro-apoptotic protein BAX and anti-apoptotic protein Bcl-2. Honokiol also significantly increased protein expression levels of ACOX1, CPT1, p-HSL, and p-PLIN and reduced ROS levels, suggesting its possible role in fat oxidation and lipid catabolism. Honokiol-induced browning could be mediated by activation of ERK, as inhibition of ERK by FR180204 abolished expression of PGC-1α and UCP1. Our findings suggest that honokiol exhibits a modulatory role in adipocytes via induction of browning and apoptosis in white adipocytes, promotion of catabolic lipid metabolism, as well as activation and inhibition of apoptosis in HIB1B brown adipocytes, thereby exhibiting therapeutic potential against obesity. Copyright © 2017 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy.

PubMed

Sommariva, E; Brambilla, S; Carbucicchio, C; Gambini, E; Meraviglia, V; Dello Russo, A; Farina, F M; Casella, M; Catto, V; Pontone, G; Chiesa, M; Stadiotti, I; Cogliati, E; Paolin, A; Ouali Alami, N; Preziuso, C; d'Amati, G; Colombo, G I; Rossini, A; Capogrossi, M C; Tondo, C; Pompilio, G

2016-06-14

Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy

PubMed Central

Sommariva, E.; Brambilla, S.; Carbucicchio, C.; Gambini, E.; Meraviglia, V.; Dello Russo, A.; Farina, F.M.; Casella, M.; Catto, V.; Pontone, G.; Chiesa, M.; Stadiotti, I.; Cogliati, E.; Paolin, A.; Ouali Alami, N.; Preziuso, C.; d'Amati, G.; Colombo, G.I.; Rossini, A.; Capogrossi, M.C.; Tondo, C.; Pompilio, G.

2016-01-01

Abstract Aim Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. Methods and results We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. controls. Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. Conclusions Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies. PMID:26590176

Direct and indirect effects of leptin on adipocyte metabolism.

PubMed

Harris, Ruth B S

2014-03-01

Leptin is hypothesized to function as a negative feedback signal in the regulation of energy balance. It is produced primarily by adipose tissue and circulating concentrations correlate with the size of body fat stores. Administration of exogenous leptin to normal weight, leptin responsive animals inhibits food intake and reduces the size of body fat stores whereas mice that are deficient in either leptin or functional leptin receptors are hyperphagic and obese, consistent with a role for leptin in the control of body weight. This review discusses the effect of leptin on adipocyte metabolism. Because adipocytes express leptin receptors there is the potential for leptin to influence adipocyte metabolism directly. Adipocytes also are insulin responsive and receive sympathetic innervation, therefore leptin can also modify adipocyte metabolism indirectly. Studies published to date suggest that direct activation of adipocyte leptin receptors has little effect on cell metabolism in vivo, but that leptin modifies adipocyte sensitivity to insulin to inhibit lipid accumulation. In vivo administration of leptin leads to a suppression of lipogenesis, an increase in triglyceride hydrolysis and an increase in fatty acid and glucose oxidation. Activation of central leptin receptors also contributes to the development of a catabolic state in adipocytes, but this may vary between different fat depots. Leptin reduces the size of white fat depots by inhibiting cell proliferation both through induction of inhibitory circulating factors and by contributing to sympathetic tone which suppresses adipocyte proliferation. This article is part of a Special Issue entitled: Modulation of Adipose Tissue in Health and Disease. Copyright © 2013 Elsevier B.V. All rights reserved.

KLF15 promotes transcription of KLF3 gene in bovine adipocytes.

PubMed

Guo, Hongfang; Khan, Rajwali; Raza, Sayed Haidar Abbas; Ning, Yue; Wei, Dawei; Wu, Sen; Hosseini, Seyed Mahdi; Ullah, Irfan; Garcia, Matthew D; Zan, Linsen

2018-06-15

The Krüppel-like factors (KLF) family plays an important role in adipogenesis, which is subject to internal hierarchical regulation. KLF3 is a member of KLF family, mainly responsible for adipocyte differentiation and fat deposition. However, the transcriptional regulation of bovine KLF3 gene and its relationship with KLF15 gene remains unclear during bovine adipogenesis. Here, we report that the expression pattern of KLF3 and KLF15 genes during bovine adipogenesis, when KLF15 gene was overexpressed through adenoviral vector (Ad-KLF15) in bovine adipocytes the expression level of KLF3 gene was increased, similarly when KLF15 was down regulated through siRNA the expression level of KLF3 was also reduced. To explore the transcriptional regulation of bovine KLF3 gene and its relationship with KLF15, serial deletion constructs of the 5'flanking region of bovine KLF3gene revealed through dual-luciferase reporter assay that the core promoter is located in -264 to -76 regions. The most proximal GGGG element in the promoter of the bovine KLF3 gene (located in -264 to -76 regions) is required for promotion by KLF15. Electrophoretic mobility shift (EMSA) and chromatin immunoprecipitation (ChIP) assays further confirmed that KLF15 gene binds to the KLF3 gene core promoter region in bovine adipocytes. These findings conclude that KLF15 promotes the transcriptional activity of KLF3 in bovine adipocytes. This mechanism to provides a new direction for further study of adipogenesis by internal regulation of members within KLF family. Copyright © 2018 Elsevier B.V. All rights reserved.

Differentiation to adipocytes in accompanied by an increase in the amounts of Gi- and Go-proteins in 3T3-L1 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Watkins, D.C.; Northup, J.K.; Malbon, C.C.

Treatment of cultures of 3T3-L1 cells with methylisobutyl-xanthine and dexamethasone has been shown to result in accumulation of lipid and conversion to the morphology of adipocytes in more than 90% of the cells. The status of the stimulatory (Gs), inhibitory (Gi) and Go-proteins during the course of 3T3-L1 differentiation was examined. The amount of alpha subunit of Gs (..cap alpha..Gs), assayed by radiolabeling in the presence of cholera toxin and (/sup 32/P)NAD/sup +/, increased upon differentiation as previously described by others. The amounts of ..cap alpha..Gi and ..cap alpha..Go assayed by radiolabeling in the presence of pertussis toxin and (/supmore » 32/P)NAD/sup +/ increased 3-fold upon differentiation. Immunoblots of cell membranes subjected to gel electrophoresis in sodium dodecyl sulfate were probed with two rabbit antisera raised against bovine brain ..cap alpha..Go and with one raised against the..beta..-subunit of the bovine rod-outer-segment G-protein, referred to as transducin. The immunoblotting data confirm the increase upon differentiation of ..cap alpha..Go and also demonstrate an increase in the amount of the ..beta..-subunit. Thus differentiation of 3T3-L1 cells is accompanied by dramatic changes in the complexion of G-proteins in the membranes.« less

Body fat mass and the proportion of very large adipocytes in pregnant women are associated with gestational insulin resistance.

PubMed

Svensson, H; Wetterling, L; Bosaeus, M; Odén, B; Odén, A; Jennische, E; Edén, S; Holmäng, A; Lönn, M

2016-04-01

Pregnancy is accompanied by fat gain and insulin resistance. Changes in adipose tissue morphology and function during pregnancy and factors contributing to gestational insulin resistance are incompletely known. We sought to characterize adipose tissue in trimesters 1 and 3 (T1/T3) in normal weight (NW) and obese pregnant women, and identify adipose tissue-related factors associated with gestational insulin resistance. Twenty-two NW and 11 obese women were recruited early in pregnancy for the Pregnancy Obesity Nutrition and Child Health study. Examinations and sampling of blood and abdominal adipose tissue were performed longitudinally in T1/T3 to determine fat mass (air-displacement plethysmography); insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR); size, number and lipolytic activity of adipocytes; and adipokine release and density of immune cells and blood vessels in adipose tissue. Fat mass and HOMA-IR increased similarly between T1 and T3 in the groups; all remained normoglycemic. Adipocyte size increased in NW women. Adipocyte number was not influenced, but proportions of small and large adipocytes changed oppositely in the groups. Lipolytic activity and circulating adipocyte fatty acid-binding protein increased in both groups. Adiponectin release was reduced in NW women. Fat mass and the proportion of very large adipocytes were most strongly associated with T3 HOMA-IR by multivariable linear regression (R(2)=0.751, P<0.001). During pregnancy, adipose tissue morphology and function change comprehensively. NW women accumulated fat in existing adipocytes, accompanied by reduced adiponectin release. In comparison with the NW group, obese women had signs of adipocyte recruitment and maintained adiponectin levels. Body fat and large adipocytes may contribute significantly to gestational insulin resistance.

Adipocyte-derived players in hematologic tumors: useful novel targets?

PubMed

Jöhrer, Karin; Ploner, Christian; Thangavadivel, Shanmugapriya; Wuggenig, Philipp; Greil, Richard

2015-01-01

Adipocytes and their products play essential roles in tumor establishment and progression. As the main cellular component of the bone marrow, adipocytes may contribute to the development of hematologic tumors. This review summarizes experimental data on adipocytes and their interaction with various cancer cells. Special focus is set on the interactions of bone marrow adipocytes and normal and transformed cells of the hematopoietic system such as myeloma and leukemia cells. Current in vitro and in vivo data are summarized and the potential of novel therapeutic targets is critically discussed. Targeting lipid metabolism of cancer cells and adipocytes in combination with standard therapeutics might open novel therapeutic avenues in these cancer entities. Adipocyte-derived products such as free fatty acids and specific adipokines such as adiponectin may be vital anti-cancer targets in hematologic malignancies. However, available data on lipid metabolism is currently mostly referring to peripheral fat cell/cancer cell interactions and results need to be evaluated specifically for the bone marrow niche.

Differential dephosphorylation of the insulin receptor and its 160-kDa substrate (pp160) in rat adipocytes.

PubMed

Mooney, R A; Bordwell, K L

1992-07-15

A permeabilized rat adipocyte model was developed which permitted an examination of: 1) insulin receptor autophosphorylation, 2) phosphorylation of a putative insulin receptor substrate of 160 kDa, pp160, and 3) the dephosphorylation reactions associated with each of these phosphoproteins. Rat adipocytes, preincubated with [32P]orthophosphate for 2 h, were exposed to insulin (10(-7) M) at the time of digitonin permeabilization. Phosphorylation of pp160 and autophosphorylation of the insulin receptor increased as a function of Mn2+ concentration in the media with near maximum responses at 10 mM. Maximum response was at least as large as the intact cell response to 10(-7) M insulin. In contrast, magnesium did not increase phosphorylation of pp160 although an increase in receptor autophosphorylation was observed. Autophosphorylation was preserved at digitonin concentrations of 20-100 micrograms/ml, but pp160 phosphorylation was negligible beyond 40 micrograms/ml. Our previous work demonstrated that the insulin receptor was associated with a phosphotyrosine phosphatase activity in permeabilized adipocytes (Mooney, R., and Anderson, D. (1989) J. Biol. Chem. 264, 6850-6857). The current permeabilized adipocyte model made possible an examination of the effects of phosphotyrosine phosphatase inhibitors, including several divalent metal cations (Zn2+, Co2+, and Ni2+), vanadate, and molybdate on both net phosphorylation of pp160 and autophosphorylation of the insulin receptor. Zn2+ at 100 microM, Ni2+ at 1 mM, and Co2+ at 1 or 5 mM increased insulin-dependent phosphorylation of pp160 at least 5-fold and autophosphorylation 2-fold. At higher concentrations of Zn2+ (1 mM) and Ni2+ (5 mM), however, no increase in phosphorylation of pp160 was observed and autophosphorylation was inhibited. Vanadate (1 mM) and molybdate (100 microM) increased insulin-dependent phosphorylation of pp160 by 3-fold when tested separately and 7-fold in combination. Insulin receptor autophosphorylation

Fluorescence lifetime imaging of lipids during 3T3-L1 cell differentiation

NASA Astrophysics Data System (ADS)

Song, Young Sik; Won, Young Jae; Lee, Sang-Hak; Kim, Dug Young

2014-03-01

Obesity is becoming a big health problem in these days. Since increased body weight is due to increased number and size of the triglyceride-storing adipocytes, many researchers are working on differentiation conditions and processes of adipocytes. Adipocytes also work as regulators of whole-body energy homeostasis by secreting several proteins that regulate processes as diverse as haemostasis, blood pressure, immune function, angiogenesis and energy balance. 3T3-L1 cells are widely used cell line for studying adipogenesis because it can differentiate into an adipocyte-like phenotype under appropriate conditions. In this paper, we propose an effective fluorescence lifetime imaging technique which can easily distinguish lipids in membrane and those in lipid droplets. Nile red dyes are attached to lipids in 3T3-L1 cells. Fluorescence lifetime images were taken for 2 week during differentiation procedure of 3T3-L1 cells into adipocytes. We used 488 nm pulsed laser with 5MHz repetition rate and emission wavelength is 520 nm of Nile Red fluorescent dye. Results clearly show that the lifetime of Nile red in lipid droplets are smaller than those in cell membrane. Our results suggest that fluorescence lifetime imaging can be a very powerful tool to monitor lipid droplet formation in adipocytes from 3T3-L1 cells.

Progeny from dedifferentiated adipocytes display protracted adipogenesis

USDA-ARS?s Scientific Manuscript database

Progeny of adipofibroblast cells, derived from mature bovine adipocytes, were used to determine their ability to redifferentiate into lipid-assimilating adipocytes. Traditional cell biology methods were used, including the expression of adipogenic markers such as PPAR'. When exposed to medium supple...

Activated AMPK and prostaglandins are involved in the response to conjugated linoleic acid and are sufficient to cause lipid reductions in adipocytes.

PubMed

Jiang, Shan; Chen, Han; Wang, Zhigang; Riethoven, Jean-Jack; Xia, Yuannan; Miner, Jess; Fromm, Michael

2011-07-01

trans-10, cis-12 Conjugated linoleic acid (t10c12 CLA) reduces triglyceride levels in adipocytes. AMP-activated protein kinase (AMPK) and inflammation were recently demonstrated to be involved in the emerging pathways regulating this response. This study further investigated the role of AMPK and inflammation by testing the following hypotheses: (1) a moderate activation of AMPK and an inflammatory response are sufficient to reduce triglycerides, and (2) strong activation of AMPK is also sufficient. Experiments were performed by adding compounds that affect these pathways and by measuring their effects in 3T3-L1 adipocytes. A comparison of four AMPK activators (metformin, phenformin, TNF-α and t10c12 CLA) found a correlation between AMPK activity and triglyceride reduction. This correlation appeared to be modulated by the level of cyclo-oxygenase (COX)-2 mRNA produced. Inhibitors of the prostaglandin (PG) biosynthetic pathway interfered with t10c12 CLA's ability to reduce triglycerides. A combination of metformin and PGH2, or phenformin alone, efficiently reduced triglyceride levels in adipocytes. Microarray analysis indicated that the transcriptional responses to phenformin or t10c12 CLA were very similar, suggesting similar pathways were activated. 3T3-L1 fibroblasts were found to weakly induce the integrated stress response (ISR) in response to phenformin or t10c12 CLA and to respond robustly as they differentiated into adipocytes. This indicated that both chemicals required adipocytes at the same stage of differentiation to be competent for this response. These results support the above hypotheses and suggest compounds that moderately activate AMPK and increase PG levels or robustly activate AMPK in adipocytes may be beneficial for reducing adiposity. Copyright © 2011 Elsevier Inc. All rights reserved.

Lipid droplets fusion in adipocyte differentiated 3T3-L1 cells: A Monte Carlo simulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boschi, Federico, E-mail: federico.boschi@univr.it; Department of Computer Science, University of Verona, Strada Le Grazie 15, 37134 Verona; Rizzatti, Vanni

Several human worldwide diseases like obesity, type 2 diabetes, hepatic steatosis, atherosclerosis and other metabolic pathologies are related to the excessive accumulation of lipids in cells. Lipids accumulate in spherical cellular inclusions called lipid droplets (LDs) whose sizes range from fraction to one hundred of micrometers in adipocytes. It has been suggested that LDs can grow in size due to a fusion process by which a larger LD is obtained with spherical shape and volume equal to the sum of the progenitors’ ones. In this study, the size distribution of two populations of LDs was analyzed in immature and maturemore » (5-days differentiated) 3T3-L1 adipocytes (first and second populations, respectively) after Oil Red O staining. A Monte Carlo simulation of interaction between LDs has been developed in order to quantify the size distribution and the number of fusion events needed to obtain the distribution of the second population size starting from the first one. Four models are presented here based on different kinds of interaction: a surface weighted interaction (R2 Model), a volume weighted interaction (R3 Model), a random interaction (Random model) and an interaction related to the place where the LDs are born (Nearest Model). The last two models mimic quite well the behavior found in the experimental data. This work represents a first step in developing numerical simulations of the LDs growth process. Due to the complex phenomena involving LDs (absorption, growth through additional neutral lipid deposition in existing droplets, de novo formation and catabolism) the study focuses on the fusion process. The results suggest that, to obtain the observed size distribution, a number of fusion events comparable with the number of LDs themselves is needed. Moreover the MC approach results a powerful tool for investigating the LDs growth process. Highlights: • We evaluated the role of the fusion process in the synthesis of the lipid droplets. • We

Body fat mass and the proportion of very large adipocytes in pregnant women are associated with gestational insulin resistance

PubMed Central

Svensson, H; Wetterling, L; Bosaeus, M; Odén, B; Odén, A; Jennische, E; Edén, S; Holmäng, A; Lönn, M

2016-01-01

Background/Objectives: Pregnancy is accompanied by fat gain and insulin resistance. Changes in adipose tissue morphology and function during pregnancy and factors contributing to gestational insulin resistance are incompletely known. We sought to characterize adipose tissue in trimesters 1 and 3 (T1/T3) in normal weight (NW) and obese pregnant women, and identify adipose tissue-related factors associated with gestational insulin resistance. Subjects/Methods: Twenty-two NW and 11 obese women were recruited early in pregnancy for the Pregnancy Obesity Nutrition and Child Health study. Examinations and sampling of blood and abdominal adipose tissue were performed longitudinally in T1/T3 to determine fat mass (air-displacement plethysmography); insulin resistance (homeostasis model assessment of insulin resistance, HOMA-IR); size, number and lipolytic activity of adipocytes; and adipokine release and density of immune cells and blood vessels in adipose tissue. Results: Fat mass and HOMA-IR increased similarly between T1 and T3 in the groups; all remained normoglycemic. Adipocyte size increased in NW women. Adipocyte number was not influenced, but proportions of small and large adipocytes changed oppositely in the groups. Lipolytic activity and circulating adipocyte fatty acid-binding protein increased in both groups. Adiponectin release was reduced in NW women. Fat mass and the proportion of very large adipocytes were most strongly associated with T3 HOMA-IR by multivariable linear regression (R2=0.751, P<0.001). Conclusions: During pregnancy, adipose tissue morphology and function change comprehensively. NW women accumulated fat in existing adipocytes, accompanied by reduced adiponectin release. In comparison with the NW group, obese women had signs of adipocyte recruitment and maintained adiponectin levels. Body fat and large adipocytes may contribute significantly to gestational insulin resistance. PMID:26563815

Impaired response of mature adipocytes of diabetic mice to hypoxia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Seok Jong, E-mail: seok-hong@northwestern.edu; Jin, Da P.; Buck, Donald W.

2011-10-01

Adipose tissue contains various cells such as infiltrated monocytes/macrophages, endothelial cells, preadipocytes, and adipocytes. Adipocytes have an endocrine function by secreting adipokines such as interleukin (IL)-6, tumor necrosis factor (TNF)-{alpha}, leptin, and adiponectin. Dysregulation of adipokines in adipose tissues leads to a chronic low-grade inflammation which could result in atherosclerosis, hypertension, and type 2 diabetes. A sustained inflammatory state, which is characterized by prolonged persistence of macrophages and neutrophils, is found in diabetic wounds. In addition, subcutaneous adipocytes are enormously increased in amount clinically in type 2 diabetes. However, the function of subcutaneous adipocytes, which play an important role inmore » injured tissue subjected to hypoxia, has not been well characterized in vitro due to the difficulty of maintaining mature adipocytes in culture using conventional methods because of their buoyancy. In this study, we established a novel in vitro culture method of mature adipocytes by enclosing them in a hyaluronan (HA) based hydrogel to study their role in response to stress such as hypoxia. BrdU labeling and Ki67 immunostaining experiments showed that hydrogel enclosed mature adipocytes proliferate in vitro. Both mRNA and protein expression analyses for hypoxia regulated genes, such as vascular endothelial growth factor (VEGF) and heme oxygenase 1 (HO1), showed that mature adipocytes of wild type mice respond to hypoxia. In contrast, mature adipocytes of diabetic db/db and TallyHo mice did not efficiently respond to hypoxia. Our studies suggest that mature adipocytes are functionally active cells, and their abnormal function to hypoxia can be one of underlining mechanisms in type 2 diabetes.« less

Inhibition of Adipogenesis and Induction of Apoptosis and Lipolysis by Stem Bromelain in 3T3-L1 Adipocytes

PubMed Central

Dave, Sandeep; Kaur, Naval Jit; Nanduri, Ravikanth; Dkhar, H. Kitdorlang; Kumar, Ashwani; Gupta, Pawan

2012-01-01

The phytotherapeutic protein stem bromelain (SBM) is used as an anti-obesity alternative medicine. We show at the cellular level that SBM irreversibly inhibits 3T3-L1 adipocyte differentiation by reducing adipogenic gene expression and induces apoptosis and lipolysis in mature adipocytes. At the molecular level, SBM suppressed adipogenesis by downregulating C/EBPα and PPARγ independent of C/EBPβ gene expression. Moreover, mRNA levels of adipocyte fatty acid-binding protein (ap2), fatty acid synthase (FAS), lipoprotein lipase (LPL), CD36, and acetyl-CoA carboxylase (ACC) were also downregulated by SBM. Additionally, SBM reduced adiponectin expression and secretion. SBM's ability to repress PPARγ expression seems to stem from its ability to inhibit Akt and augment the TNFα pathway. The Akt–TSC2–mTORC1 pathway has recently been described for PPARγ expression in adipocytes. In our experiments, TNFα upregulation compromised cell viability of mature adipocytes (via apoptosis) and induced lipolysis. Lipolytic response was evident by downregulation of anti-lipolytic genes perilipin, phosphodiestersae-3B (PDE3B), and GTP binding protein Giα1, as well as sustained expression of hormone sensitive lipase (HSL). These data indicate that SBM, together with all-trans retinoic-acid (atRA), may be a potent modulator of obesity by repressing the PPARγ-regulated adipogenesis pathway at all stages and by augmenting TNFα-induced lipolysis and apoptosis in mature adipocytes. PMID:22292054

Chlamydia pneumoniae exploits adipocyte lipid chaperone FABP4 to facilitate fat mobilization and intracellular growth in murine adipocytes.

PubMed

Walenna, Nirwana Fitriani; Kurihara, Yusuke; Chou, Bin; Ishii, Kazunari; Soejima, Toshinori; Itoh, Ryota; Shimizu, Akinori; Ichinohe, Takeshi; Hiromatsu, Kenji

2018-01-01

Fatty acid-binding protein 4 (FABP4), a cytosolic lipid chaperone predominantly expressed in adipocytes and macrophages, modulates lipid fluxes, trafficking, signaling, and metabolism. Recent studies have demonstrated that FABP4 regulates metabolic and inflammatory pathways, and in mouse models its inhibition can improve type 2 diabetes mellitus and atherosclerosis. However, the role of FABP4 in bacterial infection, metabolic crosstalk between host and pathogen, and bacterial pathogenesis have not been studied. As an obligate intracellular pathogen, Chlamydia pneumoniae needs to obtain nutrients such as ATP and lipids from host cells. Here, we show that C. pneumoniae successfully infects and proliferates in murine adipocytes by inducing hormone sensitive lipase (HSL)-mediated lipolysis. Chemical inhibition or genetic manipulation of HSL significantly abrogated the intracellular growth of C. pneumoniae in adipocytes. Liberated free fatty acids were utilized to generate ATP via β-oxidation, which C. pneumoniae usurped for its replication. Strikingly, chemical inhibition or genetic silencing of FABP4 significantly abrogated C. pneumoniae infection-induced lipolysis and mobilization of liberated FFAs, resulting in reduced bacterial growth in adipocytes. Collectively, these results demonstrate that C. pneumoniae exploits host FABP4 to facilitate fat mobilization and intracellular replication in adipocytes. This work uncovers a novel strategy used by intracellular pathogens for acquiring energy via hijacking of the host lipid metabolism pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of perfluorinated chemicals on adipocyte development ...

EPA Pesticide Factsheets

Obesity is a growing concern in the US population. Current interest is high in the role played by environmental factors called obesogens that may contribute to obesity through developmental exposure. One class of potential obesogens is the family of perfluorinated chemicals used as surfactants in a variety of industrial applications. Given the importance of understanding the role these compounds play in lipid homeostasis we used pre-adipocyte 3T3-L1 mouse fibroblast cells (Zen-Bio, RTP NC) to study their effects on adipogenesis and lipid accumulation. These cells differentiate into adipocytes accumulating large lipid droplets. Cultures were treated with perfluorooctanoic acid (PFOA) (1-200uM), perfluorononanoic acid (PFNA) (5-lOOuM), perfluorooctane sulfonate (PFOS) (5O-300uM), and perfluorohexane sulfonate (PFHxS) (40- 250uM). Cell size number, and lipid content were assessed using morphomeiric analysis. All four compounds decreased cell size compared to control, and PFNA was most potent, in terms of lowest observed effect concentration (LOEC), whereas PFOA was least potent. Cell number increased for all perfluorinated chemicals tested, most potently for PFNA and least for PFOS. Interestingly, average lipid area per cell for all four chemicals decreased compared to control, but PFOS and PFHxS had increased total lipid area. Additionally, significant increases in total triglyceride were noted for all compounds compared to controls. PFOA and PFNA increased trigly

Xenobiotics that affect oxidative phosphorylation alter differentiation of human adipose-derived stem cells at concentrations that are found in human blood

PubMed Central

Llobet, Laura; Toivonen, Janne M.; Montoya, Julio; Ruiz-Pesini, Eduardo; López-Gallardo, Ester

2015-01-01

ABSTRACT Adipogenesis is accompanied by differentiation of adipose tissue-derived stem cells to adipocytes. As part of this differentiation, biogenesis of the oxidative phosphorylation system occurs. Many chemical compounds used in medicine, agriculture or other human activities affect oxidative phosphorylation function. Therefore, these xenobiotics could alter adipogenesis. We have analyzed the effects on adipocyte differentiation of some xenobiotics that act on the oxidative phosphorylation system. The tested concentrations have been previously reported in human blood. Our results show that pharmaceutical drugs that decrease mitochondrial DNA replication, such as nucleoside reverse transcriptase inhibitors, or inhibitors of mitochondrial protein synthesis, such as ribosomal antibiotics, diminish adipocyte differentiation and leptin secretion. By contrast, the environmental chemical pollutant tributyltin chloride, which inhibits the ATP synthase of the oxidative phosphorylation system, can promote adipocyte differentiation and leptin secretion, leading to obesity and metabolic syndrome as postulated by the obesogen hypothesis. PMID:26398948

Municipal wastewater affects adipose deposition in male mice and increases 3T3-L1 cell differentiation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Biasiotto, Giorgio; Zanella, Isabella; Department of Molecular and Translational Medicine, University of Brescia, Brescia

Trace concentration of EDs (endocrine disrupting compounds) in water bodies caused by wastewater treatment plant effluents is a recognized problem for the health of aquatic organisms and their potential to affect human health. In this paper we show that continuous exposure of male mice from early development to the adult life (140 days) to unrestricted drinking of wastewater collected from a municipal sewage treatment plant, is associated with an increased adipose deposition and weight gain during adulthood because of altered body homeostasis. In parallel, bisphenol A (BPA) at the administration dose of 5 μg/kg/body weight, shows an increasing effect onmore » total body weight and fat mass. In vitro, a solid phase extract (SPE) of the wastewater (eTW), caused stimulation of 3T3-L1 adipocyte differentiation at dilutions of 0.4 and 1 % in the final culture medium which contained a concentration of BPA of 40 nM and 90 nM respectively. Pure BPA also promoted adipocytes differentiation at the concentration of 50 and 80 μM. BPA effect in 3T3-L1 cells was associated to the specific activation of the estrogen receptor alpha (ERα) in undifferentiated cells and the estrogen receptor beta (ERβ) in differentiated cells. BPA also activated the Peroxisome Proliferator Activated Receptor gamma (PPARγ) upregulating a minimal 3XPPARE luciferase reporter and the PPARγ-target promoter of the aP2 gene in adipose cells, while it was not effective in preadipocytes. The pure estrogen receptor agonist diethylstilbestrol (DES) played an opposite action to that of BPA inhibiting PPARγ activity in adipocytes, preventing cell differentiation, activating ERα in preadipocytes and inhibiting ERα and ERβ regulation in adipocytes. The results of this work show that the drinking of chemically-contaminated wastewater promotes fat deposition in male mice and that EDs present in sewage are likely responsible for this effect through a nuclear receptor-mediated mechanism. - Highlights: �

Accumulation of Polychlorinated Biphenyls in Adipocytes: Selective Targeting to Lipid Droplets and Role of Caveolin-1

PubMed Central

Bourez, Sophie; Le Lay, Soazig; Van den Daelen, Carine; Louis, Caroline; Larondelle, Yvan; Thomé, Jean-Pierre; Schneider, Yves-Jacques; Dugail, Isabelle; Debier, Cathy

2012-01-01

Background Polychlorinated biphenyls (PCBs) are persistent environmental pollutants that preferentially accumulate in lipid-rich tissues of contaminated organisms. Although the adipose tissue constitutes a major intern reservoir of PCBs and recent epidemiological studies associate PCBs to the development of obesity and its related disorders, little is known about the mechanisms involved in their uptake by the adipose tissue and their intracellular localization in fat cells. Methodology/Principal Findings We have examined the intracellular distribution of PCBs in mouse cultured adipocytes and tested the potential involvement of caveolin-1, an abundant adipocyte membrane protein, in the uptake of these compounds by fat cells. We show that 2,4,4′-trichlorobiphenyl (PCB-28), 2,3′,4,4′,5-pentachlorobiphenyl (PCB-118) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB-153) congeners rapidly and extensively accumulate in 3T3-L1 or mouse embryonic fibroblast (MEF) derived cultured adipocytes. The dynamics of accumulation differed between the 3 congeners tested. By subcellular fractionation of primary adipocytes, we demonstrate that these pollutants were almost exclusively recovered within the lipid droplet fraction and practically not associated to cell membranes. The absence of caveolin-1 expression in primary adipocytes from cav-1 deficient mice did not modify lipid droplet selective targeting of PCBs. In cav-1 KO MEF differentiated adipocytes, PCB accumulation was decreased, which correlated with reduced cell triglyceride content. Conversely, adenoviral mediated cav-1 overexpressing in 3T3-L1 cells, which had no impact on total cell lipid content, did not change PCB accumulation. Conclusion/Significance Our data indicate that caveolin-1 per se is not required for selective PCB accumulation, but rather point out a primary dependence on adipocyte triglyceride content. If the crucial role of lipid droplets in energy homeostasis is considered, the almost exclusive

Utility of Adipocyte Fractions in Fat Grafting in an Athymic Rat Model.

PubMed

Akgul, Yucel; Constantine, Ryan; Bartels, Mason; Scherer, Philipp; Davis, Kathryn; Kenkel, Jeffrey M

2018-05-02

Multiple processing and handling methods of autologous fat yields to variations in graft retention and viability, which results in unpredictable clinical outcomes. This study aims to understand the skin effects of fat graft preparations that contain a varying ratio of free-lipid and stem-cell-bearing stromal vascular fractions (SVF). Lipoaspirates from consenting patients were processed into emulsified fat and then SVF and adipocyte fractions (free-lipid). SVF enriched with 0%, 5%, and 15% free-lipid were grafted along the dorsum of athymic rats. The xenografts were collected 45 days after grafting and then prepped for immunostaining. Xenografts resulted in viable tissue mass under the panniculus carnosus of rats as confirmed with human specific markers. A low percentage of human cells was also detected in the lower reticular dermis. Although grafts with SVF formed adipocytes of normal architecture, grafts formed with free-lipid alone resulted in large lipid vacuoles in varying sizes. Among graft preparations, SVF with 10% free-lipid resulted in much-developed adipocyte architecture with collagen and elastin. Compared with SVF alone grafts, SVF with free-lipid had higher CD44 expression, suggesting a localized immune response of adipocytes. Current studies suggest that SVF enriched with approximately 10% free-lipid provides the best conditions for fat graft differentiation into viable fat tissue formation as well as collagen and elastin production to provide mechanical support for overlaying skin in an athymic rat model. Additionally, application of this therapeutic modality in a simple clinical setting may offer a practical way to concentrate SVF with free-lipid in a small volume for the improvement of clinical defects.

Molecular cloning, characterization and expression analysis of C/EBP α, β and δ in adipose-related tissues and adipocyte of duck (Anas platyrhynchos).

PubMed

Qiu, Jiamin; Wang, Wanxia; Hu, Shenqiang; Wang, Yushi; Sun, Wenqiang; Hu, Jiwei; Gan, Xiang; Wang, Jiwen

2018-07-01

CCAAT/enhancer binding protein α, β, δ (C/EBP α, β, δ) are essential transcriptional factors in regulating adipose development. However, information about their sequence characteristics and functions during adipocyte development still remains scarce in birds. In present study, we found that duck C/EBP α, β, δ differed in their phosphorylation sites and low complexity regions (LCRs) among their orthologs and paralogs. Phylogenetic analysis showed that C/EBP α, β, δ had different evolutionary patterns, and each of duck C/EBP α, β, δ was strikingly diverged from orthologs of other Aves. Results of quantitative real-time PCR exhibited that C/EBP α, β, δ were all highly expressed in duck adipose tissues. Indeed, investigations of changes in both their mRNA levels and lipid droplet content during duck adipocytes differentiation showed that their expression profiles were closely related to cellular lipid accumulation. Furthermore, hierarchical clustering analysis of the C/EBPs and lipid metabolism-related genes expression profiles showed that C/EBP α was clustered with genes related to lipolysis, lipogenesis and fatty acid desaturation, whereas C/EBP β, δ were clustered with genes related to de novo lipogenesis and fatty acid elongation, which were different from mammals. In summary, C/EBP α, β, δ of duck differ from other species in their structures and have different effects on lipid metabolism during adipocytes differentiation. This research serve as a foundation for further investigations about avian C/EBP α, β, δ in adipocytes differentiation and adipose development. Copyright © 2018 Elsevier Inc. All rights reserved.

Nymphaea nouchali Burm. f. hydroalcoholic seed extract increases glucose consumption in 3T3-L1 adipocytes through activation of peroxisome proliferator-activated receptor gamma and insulin sensitization

PubMed Central

Parimala, Mabel; Debjani, M.; Vasanthi, Hannah Rachel; Shoba, Francis Gricilda

2015-01-01

Nymphaea nouchali Burm. f. (Family – Nymphaeaceae) is a well-known medicinal plant used in the Indian ayurvedic system of medicine for treating diabetes. The seeds especially have been prescribed for diabetes. The hydroalcoholic extract of N. nouchali seeds has been demonstrated to possess anti-hyperglycemic effects in diabetic rats, but the functional mechanism remains unknown. The nuclear receptor, peroxisome proliferator-activated receptor gamma (PPARγ) is noted to play an important role in glucose and lipid homeostasis. This study was hence focused in evaluating the effect of the extract on PPARγ activation, adipocyte differentiation, and glucose consumption in 3T3-L1 cells. Cell viability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), followed by adipogenesis assay using Oil Red O technique. Glucose consumption of preadipocytes and adipocytes in the presence of the extract was also determined. Real-time polymerase chain reaction was performed to identify the expression of genes involved in glucose consumption in the adipocytes. MTT assay confirmed the extract to be nontoxic, and Oil Red O staining confirmed enhanced adipocyte differentiation of 3T3-L1 cells in a dose-dependent manner. The extract also increased the expression of PPARγ target gene, which in turn enhanced the expression of GLUT-4. The data, therefore, suggests that N. nouchali seed extract promotes adipocyte differentiation and glucose consumption by inducing PPARγ activation, which in turn increases mRNA GLUT-4 expression and subsequently enhances insulin-responsiveness in insulin target tissues. PMID:26605160

Glucose and Insulin Stimulate Lipogenesis in Porcine Adipocytes: Dissimilar and Identical Regulation Pathway for Key Transcription Factors.

PubMed

Hua, Zhang Guo; Xiong, Lu Jian; Yan, Chen; Wei, Dai Hong; YingPai, ZhaXi; Qing, Zhao Yong; Lin, Qiao Zi; Fei, Feng Ruo; Ling, Wang Ya; Ren, Ma Zhong

2016-11-30

Lipogenesis is under the concerted action of ChREBP, SREBP-1c and other transcription factors in response to glucose and insulin. The isolated porcine preadipocytes were differentiated into mature adipocytes to investigate the roles and interrelation of these transcription factors in the context of glucose- and insulin-induced lipogenesis in pigs. In ChREBP-silenced adipocytes, glucose-induced lipogenesis decreased by ~70%, however insulin-induced lipogenesis was unaffected. Moreover, insulin had no effect on ChREBP expression of unperturbed adipocytes irrespective of glucose concentration, suggesting ChREBP mediate glucose-induced lipogenesis. Insulin stimulated SREBP-1c expression and when SREBP-1c activation was blocked, and the insulin-induced lipogenesis decreased by ~55%, suggesting SREBP-1c is a key transcription factor mediating insulin-induced lipogenesis. LXRα activation promoted lipogenesis and lipogenic genes expression. In ChREBP-silenced or SREBP-1c activation blocked adipocytes, LXRα activation facilitated lipogenesis and SREBP-1c expression, but had no effect on ChREBP expression. Therefore, LXRα might mediate lipogenesis via SREBP-1c rather than ChREBP. When ChREBP expression was silenced and SREBP-1c activation blocked simultaneously, glucose and insulin were still able to stimulated lipogenesis and lipogenic genes expression, and LXRα activation enhanced these effects, suggesting LXRα mediated directly glucose- and insulin-induced lipogenesis. In summary, glucose and insulin stimulated lipogenesis through both dissimilar and identical regulation pathway in porcine adipocytes.

Cell Models and Their Application for Studying Adipogenic Differentiation in Relation to Obesity: A Review

PubMed Central

Ruiz-Ojeda, Francisco Javier; Rupérez, Azahara Iris; Gomez-Llorente, Carolina; Gil, Angel; Aguilera, Concepción María

2016-01-01

Over the last several years, the increasing prevalence of obesity has favored an intense study of adipose tissue biology and the precise mechanisms involved in adipocyte differentiation and adipogenesis. Adipocyte commitment and differentiation are complex processes, which can be investigated thanks to the development of diverse in vitro cell models and molecular biology techniques that allow for a better understanding of adipogenesis and adipocyte dysfunction associated with obesity. The aim of the present work was to update the different animal and human cell culture models available for studying the in vitro adipogenic differentiation process related to obesity and its co-morbidities. The main characteristics, new protocols, and applications of the cell models used to study the adipogenesis in the last five years have been extensively revised. Moreover, we depict co-cultures and three-dimensional cultures, given their utility to understand the connections between adipocytes and their surrounding cells in adipose tissue. PMID:27376273

Cytotoxicity and inhibitory effects of low-concentration triclosan on adipogenic differentiation of human mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guo, Li-Wu; Wu, Qiangen; Green, Bridgett

2012-07-15

Humans at all ages are continually exposed to triclosan (TCS), a widely used antimicrobial agent that can be found in many daily hygiene products, such as toothpastes and shampoos; however, the toxicological and biological effects of TCS in the human body after long-term and low-concentration exposure are far from being well understood. In the current study, we investigated the effects of TCS on the differentiation of human mesenchymal stem cells (hMSCs) by measuring the cytotoxicity, morphological changes, lipid accumulation, and the expression of adipocyte differentiation biomarkers during 21-day adipogenesis. Significant cytotoxicity was observed in un-induced hMSCs treated with high-concentration TCSmore » (≥ 5.0 μM TCS), but not with low-concentration treatments (≤ 2.5 μM TCS). TCS inhibited adipocyte differentiation of hMSCs in a concentration-dependent manner in the 0.156 to 2.5 μM range as indicated by morphological changes with Oil Red O staining, which is an index of lipid accumulation. The inhibitory effect was confirmed by a decrease in gene expression of specific adipocyte differentiation biomarkers including adipocyte protein 2, lipoprotein lipase, and adiponectin. Our study demonstrates that TCS inhibits adipocyte differentiation of hMSCs under concentrations that are not cytotoxic and in the range observed in human blood. -- Highlights: ► TCS is cytotoxic to un-induced hMSCs at concentrations ≥ 5.0 μM. ► TCS at concentrations ≤ 2.5 μM is not cytotoxic to induced hMSCs. ► TCS at non-cytotoxic concentrations inhibits lipid formation in induced hMSCs. ► TCS decreases the expression of specific biomarkers of adipocyte differentiation. ► TCS at concentrations observed in human blood inhibits adipogenesis of hMSCs.« less

Inhibition of Protein Farnesylation Arrests Adipogenesis and Affects PPARγ Expression and Activation in Differentiating Mesenchymal Stem Cells

PubMed Central

Rivas, Daniel; Akter, Rahima; Duque, Gustavo

2007-01-01

Protein farnesylation is required for the activation of multiple proteins involved in cell differentiation and function. In white adipose tissue protein, farnesylation has shown to be essential for the successful differentiation of preadipocytes into adipocytes. We hypothesize that protein farnesylation is required for PPARγ2 expression and activation, and therefore for the differentiation of human mesenchymal stem cells (MSCs) into adipocytes. MSCs were plated and induced to differentiate into adipocytes for three weeks. Differentiating cells were treated with either an inhibitor of farnesylation (FTI-277) or vehicle alone. The effect of inhibition of farnesylation in differentiating adipocytes was determined by oil red O staining. Cell survival was quantified using MTS Formazan. Additionally, nuclear extracts were obtained and prelamin A, chaperon protein HDJ-2, PPARγ, and SREBP-1 were determined by western blot. Finally, DNA binding PPARγ activity was determined using an ELISA-based PPARγ activation quantification method. Treatment with an inhibitor of farnesylation (FTI-277) arrests adipogenesis without affecting cell survival. This effect was concomitant with lower levels of PPARγ expression and activity. Finally, accumulation of prelamin A induced an increased proportion of mature SREBP-1 which is known to affect PPARγ activity. In summary, inhibition of protein farnesylation arrests the adipogenic differentiation of MSCs and affects PPARγ expression and activity. PMID:18274630

Adipocyte iron regulates leptin and food intake

PubMed Central

Gao, Yan; Li, Zhonggang; Gabrielsen, J. Scott; Simcox, Judith A.; Lee, Soh-hyun; Jones, Deborah; Cooksey, Bob; Stoddard, Gregory; Cefalu, William T.; McClain, Donald A.

2015-01-01

Dietary iron supplementation is associated with increased appetite. Here, we investigated the effect of iron on the hormone leptin, which regulates food intake and energy homeostasis. Serum ferritin was negatively associated with serum leptin in a cohort of patients with metabolic syndrome. Moreover, the same inverse correlation was observed in mice fed a high-iron diet. Adipocyte-specific loss of the iron exporter ferroportin resulted in iron loading and decreased leptin, while decreased levels of hepcidin in a murine hereditary hemochromatosis (HH) model increased adipocyte ferroportin expression, decreased adipocyte iron, and increased leptin. Treatment of 3T3-L1 adipocytes with iron decreased leptin mRNA in a dose-dependent manner. We found that iron negatively regulates leptin transcription via cAMP-responsive element binding protein activation (CREB activation) and identified 2 potential CREB-binding sites in the mouse leptin promoter region. Mutation of both sites completely blocked the effect of iron on promoter activity. ChIP analysis revealed that binding of phosphorylated CREB is enriched at these two sites in iron-treated 3T3-L1 adipocytes compared with untreated cells. Consistent with the changes in leptin, dietary iron content was also directly related to food intake, independently of weight. These findings indicate that levels of dietary iron play an important role in regulation of appetite and metabolism through CREB-dependent modulation of leptin expression. PMID:26301810

Rapamycin negatively impacts insulin signaling, glucose uptake and uncoupling protein-1 in brown adipocytes.

PubMed

García-Casarrubios, Ester; de Moura, Carlos; Arroba, Ana I; Pescador, Nuria; Calderon-Dominguez, María; Garcia, Laura; Herrero, Laura; Serra, Dolors; Cadenas, Susana; Reis, Flavio; Carvalho, Eugenia; Obregon, Maria Jesus; Valverde, Ángela M

2016-12-01

New onset diabetes after transplantation (NODAT) is a metabolic disorder that affects 40% of patients on immunosuppressive agent (IA) treatment, such as rapamycin (also known as sirolimus). IAs negatively modulate insulin action in peripheral tissues including skeletal muscle, liver and white fat. However, the effects of IAs on insulin sensitivity and thermogenesis in brown adipose tissue (BAT) have not been investigated. We have analyzed the impact of rapamycin on insulin signaling, thermogenic gene-expression and mitochondrial respiration in BAT. Treatment of brown adipocytes with rapamycin for 16h significantly decreased insulin receptor substrate 1 (IRS1) protein expression and insulin-mediated protein kinase B (Akt) phosphorylation. Consequently, both insulin-induced glucose transporter 4 (GLUT4) translocation to the plasma membrane and glucose uptake were decreased. Early activation of the N-terminal Janus activated kinase (JNK) was also observed, thereby increasing IRS1 Ser 307 phosphorylation. These effects of rapamycin on insulin signaling in brown adipocytes were partly prevented by a JNK inhibitor. In vivo treatment of rats with rapamycin for three weeks abolished insulin-mediated Akt phosphorylation in BAT. Rapamycin also inhibited norepinephrine (NE)-induced lipolysis, the expression of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and uncoupling protein (UCP)-1 in brown adipocytes. Importantly, basal mitochondrial respiration, proton leak and maximal respiratory capacity were significantly decreased in brown adipocytes treated with rapamycin. In conclusion, we demonstrate, for the first time the important role of brown adipocytes as target cells of rapamycin, suggesting that insulin resistance in BAT might play a major role in NODAT development. Copyright © 2016 Elsevier B.V. All rights reserved.

Adipogenic Differentiation of Mesenchymal Stem Cells Alters Their Immunomodulatory Properties in a Tissue-Specific Manner.

PubMed

Munir, Hafsa; Ward, Lewis S C; Sheriff, Lozan; Kemble, Samuel; Nayar, Saba; Barone, Francesca; Nash, Gerard B; McGettrick, Helen M

2017-06-01

Chronic inflammation is associated with formation of ectopic fat deposits that might represent damage-induced aberrant mesenchymal stem cell (MSC) differentiation. Such deposits are associated with increased levels of inflammatory infiltrate and poor prognosis. Here we tested the hypothesis that differentiation from MSC to adipocytes in inflamed tissue might contribute to chronicity through loss of immunomodulatory function. We assessed the effects of adipogenic differentiation of MSC isolated from bone marrow or adipose tissue on their capacity to regulate neutrophil recruitment by endothelial cells and compared the differentiated cells to primary adipocytes from adipose tissue. Bone marrow derived MSC were immunosuppressive, inhibiting neutrophil recruitment to TNFα-treated endothelial cells (EC), but MSC-derived adipocytes were no longer able to suppress neutrophil adhesion. Changes in IL-6 and TGFβ1 signalling appeared critical for the loss of the immunosuppressive phenotype. In contrast, native stromal cells, adipocytes derived from them, and mature adipocytes from adipose tissue were all immunoprotective. Thus disruption of normal tissue stroma homeostasis, as occurs in chronic inflammatory diseases, might drive "abnormal" adipogenesis which adversely influences the behavior of MSC and contributes to pathogenic recruitment of leukocytes. Interestingly, stromal cells programmed in native fat tissue retain an immunoprotective phenotype. Stem Cells 2017;35:1636-1646. © 2017 The Authors STEM CELLS published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

The adipocyte as an important target cell for Trypanosoma cruzi infection.

PubMed

Combs, Terry P; Nagajyothi; Mukherjee, Shankar; de Almeida, Cecilia J G; Jelicks, Linda A; Schubert, William; Lin, Ying; Jayabalan, David S; Zhao, Dazhi; Braunstein, Vicki L; Landskroner-Eiger, Shira; Cordero, Aisha; Factor, Stephen M; Weiss, Louis M; Lisanti, Michael P; Tanowitz, Herbert B; Scherer, Philipp E

2005-06-24

Adipose tissue plays an active role in normal metabolic homeostasis as well as in the development of human disease. Beyond its obvious role as a depot for triglycerides, adipose tissue controls energy expenditure through secretion of several factors. Little attention has been given to the role of adipocytes in the pathogenesis of Chagas disease and the associated metabolic alterations. Our previous studies have indicated that hyperglycemia significantly increases parasitemia and mortality in mice infected with Trypanosoma cruzi. We determined the consequences of adipocyte infection in vitro and in vivo. Cultured 3T3-L1 adipocytes can be infected with high efficiency. Electron micrographs of infected cells revealed a large number of intracellular parasites that cluster around lipid droplets. Furthermore, infected adipocytes exhibited changes in expression levels of a number of different adipocyte-specific or adipocyte-enriched proteins. The adipocyte is therefore an important target cell during acute Chagas disease. Infection of adipocytes by T. cruzi profoundly influences the pattern of adipokines. During chronic infection, adipocytes may represent an important long-term reservoir for parasites from which relapse of infection can occur. We have demonstrated that acute infection has a unique metabolic profile with a high degree of local inflammation in adipose tissue, hypoadiponectinemia, hypoglycemia, and hypoinsulinemia but with relatively normal glucose disposal during an oral glucose tolerance test.

Complementary Roles of Estrogen-Related Receptors in Brown Adipocyte Thermogenic Function

PubMed Central

Gantner, Marin L.; Hazen, Bethany C.; Eury, Elodie; Brown, Erin L.

2016-01-01

Brown adipose tissue (BAT) thermogenesis relies on a high abundance of mitochondria and the unique expression of the mitochondrial Uncoupling Protein 1 (UCP1), which uncouples substrate oxidation from ATP synthesis. Adrenergic stimulation of brown adipocytes activates UCP1-mediated thermogenesis; it also induces the expression of Ucp1 and other genes important for thermogenesis, thereby endowing adipocytes with higher oxidative and uncoupling capacities. Adipocyte mitochondrial biogenesis and oxidative capacity are controlled by multiple transcription factors, including the estrogen-related receptor (ERR)α. Whole-body ERRα knockout mice show decreased BAT mitochondrial content and oxidative function but normal induction of Ucp1 in response to cold. In addition to ERRα, brown adipocytes express ERRβ and ERRγ, 2 nuclear receptors that are highly similar to ERRα and whose function in adipocytes is largely unknown. To gain insights into the roles of all 3 ERRs, we assessed mitochondrial function and adrenergic responses in primary brown adipocytes lacking combinations of ERRs. We show that adipocytes lacking just ERRα, the most abundant ERR, show only mild mitochondrial defects. Adipocytes lacking ERRβ and ERRγ also show just mild defects. In contrast, adipocytes lacking all 3 ERRs have severe reductions in mitochondrial content and oxidative capacity. Moreover, adipocytes lacking all 3 ERRs have defects in the transcriptional and metabolic response to adrenergic stimulation, suggesting a wider role of ERRs in BAT function than previously appreciated. Our study shows that ERRs have a great capacity to compensate for each other in protecting mitochondrial function and the metabolic response to adrenergic signaling, processes vital to BAT function. PMID:27763777

Effects of strontium on proliferation and differentiation of rat bone marrow mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yunfeng; Li, Jihua; Zhu, Songsong

Highlights: Black-Right-Pointing-Pointer Strontium ranelate (SrR) inhibits proliferation of BMMSCs. Black-Right-Pointing-Pointer SrR increases osteoblastic but decreases adipocytic differentiation of BMMSCs. Black-Right-Pointing-Pointer SrR increases expression of Runx2, BSP and OCN by BMMSCs in osteogenic medium. Black-Right-Pointing-Pointer SrR decreases expression of PPAR{gamma}, aP2/ALBP and LPL by BMMSCs in adipogenic medium. -- Abstract: Strontium ranelate (SrR) was an effective anti-osteoporotic drug to increase bone formation and decrease bone resorption. However, reports about the effect of SR on osteoblastic and adipocytic differentiation from bone marrow mesenchymal stem cells (BMMSCs) are limited. The purpose of this study is to evaluate whether SrR affects the ability ofmore » BMMSCs to differentiate into osteoblasts or adipocytes. Rat BMMSCs were identified by flow cytometry and exposed to SR (0.1 and 1.0 mM Sr{sup 2+}) under osteogenic or adipogenic medium for 1 and 2 weeks. The proliferation and differentiation of BMMSCs were analyzed by MTT, alkaline phosphatase (ALP), Oil red O staining, quantitative real-time RT-PCR and Western blot assays. SrR significantly inhibited the proliferation, increased osteoblastic but decreased adipocytic differentiation of rat BMMSCs dose-dependently. In osteogenic medium, SrR increased the expression of ALP, the mRNA levels of Cbfa1/Runx2, bone sialoprotein, and osteocalcin by RT-PCR, and the protein levels of Cbfa1/Runx2 by Western blot. In adipogenic medium, SrR decreased the mRNA levels of PPAR{gamma}2, adipocyte lipid-binding protein 2 (aP2/ALBP), and lipoprotein lipase (LPL) by RT-PCR, and the protein expression of PPAR{gamma} in Western blot analysis. These results indicated that the effects of SrR to promote osteoblastic but inhibit adipocytic differentiation of BMMSCs might contribute to its effect on osteoporosis treatment.« less

Effects of arecoline on adipogenesis, lipolysis, and glucose uptake of adipocytes-A possible role of betel-quid chewing in metabolic syndrome

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hsu, Hsin-Fen; Tsou, Tsui-Chun, E-mail: tctsou@nhri.org.t; Chao, How-Ran

To investigate the possible involvement of betel-quid chewing in adipocyte dysfunction, we determined the effects of arecoline, a major alkaloid in areca nuts, on adipogenic differentiation (adipogenesis), lipolysis, and glucose uptake by fat cells. Using mouse 3T3-L1 preadipocytes, we showed that arecoline inhibited adipogenesis as determined by oil droplet formation and adipogenic marker gene expression. The effects of arecoline on lipolysis of differentiated 3T3-L1 adipocytes were determined by the glycerol release assay, indicating that arecoline induced lipolysis in an adenylyl cyclase-dependent manner. The diabetogenic effects of arecoline on differentiated 3T3-L1 adipocytes were evaluated by the glucose uptake assay, revealing thatmore » {>=} 300 {mu}M arecoline significantly attenuated insulin-induced glucose uptake; however, no marked effect on basal glucose uptake was detected. Moreover, using 94 subjects that were randomly selected from a health check-up, we determined the association of betel-quid chewing with hyperlipidemia and its related risk factors. Hyperlipidemia frequency and serum triglyceride levels of betel-quid chewers were significantly higher than those of non-betel-quid chewers. In this study, we demonstrated that arecoline inhibits adipogenic differentiation, induces adenylyl cyclase-dependent lipolysis, and interferes with insulin-induced glucose uptake. Arecoline-induced fat cell dysfunction may lead to hyperlipidemia and hyperglycemia/insulin-resistance. These findings provide the first in vitro evidence of betel-quid chewing modulation of adipose cell metabolism that could contribute to the explanation of the association of this habit with metabolic syndrome disorders.« less

6-Gingerol Suppresses Adipocyte-Derived Mediators of Inflammation In Vitro and in High-Fat Diet-Induced Obese Zebra Fish.

PubMed

Choi, Jia; Kim, Kui-Jin; Kim, Byung-Hak; Koh, Eun-Jeong; Seo, Min-Jung; Lee, Boo-Yong

2017-02-01

The present study was performed to investigate the molecular mechanism of 6-gingerol on adipocyte-mediated systemic inflammation in vitro and in high-fat diet-induced obese zebra fish. 6-Gingerol decreased adipogenesis due to the suppression of adipocyte differentiation markers, including peroxisome proliferator-activated receptor gamma, CCAATT enhancer binding protein α , and adipocyte protein 2, and triglyceride synthesis enzymes, including sterol regulatory element-binding protein-1, fatty acid synthase, lysophosphatidic acid acyltransferase, and acyl-coA : diacylglycerol acyltransferase 1, in 3T3-L1. A coculture insert system using 3T3-L1 with RAW 264.7 (coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages) revealed that 6-gingerol increased anti-inflammatory cytokine interleukin-10. The expression of TNF α , monocyte chemotactic protein-1, interleukin-1 β , and interleukin-6 were decreased in the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages treated with 6-gingerol. Moreover, the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages treated with 6-gingerol inhibited the protein expression of TNF α and monocyte chemotactic protein-1 in RAW 264.7. 6-Gingerol decreased c-JUN N-terminal kinase and I kappa B kinase beta and its downstream target AP-1 expression in the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages. Furthermore, 6-gingerol decreased the expression of inducible nitric oxide synthase stimulated by the coculture insert system using fully differentiated 3T3-L1 cells with RAW 264.7 macrophages in RAW 264.7 and attenuated nitric oxide production in diet-induced obese zebra fish. Our results suggest that 6-gingerol suppresses inflammation through the regulation of the c-JUN N-terminal kinase-I kappa B kinase beta and its downstream targets. Georg Thieme Verlag KG Stuttgart · New York.

Effect of dibutyryl cyclic adenosine monophosphate on the gene expression of plasminogen activator inhibitor-1 and tissue factor in adipocytes.

PubMed

Taniguchi, Makoto; Ono, Naoko; Hayashi, Akira; Yakura, Yuwna; Takeya, Hiroyuki

2011-10-01

Hypertrophic adipocytes in obese states express the elevated levels of plasminogen activator inhibitor-1 (PAI-1) and tissue factor (TF). An increase in the intracellular concentration of cyclic adenosine monophosphate (cAMP) promotes triglyceride hydrolysis and may improve dysregulation of adipocyte metabolism. Here, we investigate the effect of dibutyryl-cAMP (a phosphodiesterase-resistant analog of cAMP) on the gene expression of PAI-1 and TF in adipocytes. Differentiated 3T3-L1 adipocytes were treated with dibutyryl-cAMP and agents that would be expected to elevate intracellular cAMP, including cilostazol (a phosphodiesterase inhibitor with anti-platelet and vasodilatory properties), isoproterenol (a beta adrenergic agonist) and forskolin (an adenylyl cyclase activator). The levels of PAI-1 and TF mRNAs were measured using real-time quantitative reverse transcription-PCR. The treatment of adipocytes with dibutyryl-cAMP resulted in the inhibition of both lipid accumulation and TF gene expression. However, PAI-1 gene expression was slightly but significantly increased by dibutyryl-cAMP. On the other hand, cilostazol inhibited the expression of PAI-1 without affecting lipid accumulation. When the adipocytes were treated with cilostazol in combination with isoproterenol or forskolin, the inhibitory effect of cilostazol on PAI-1 gene expression was counteracted, thus suggesting that inhibition by cilostazol may not be the result of intracellular cAMP accumulation by phosphodiesterase inhibition. These results suggest the implication of cAMP in regulation of the gene expression of TF and PAI-1 in adipocytes. Our findings will serve as a useful basis for further research in therapy for obesity-associated thrombosis. Copyright © 2011 Elsevier Ltd. All rights reserved.

Secreted Clusterin protein inhibits osteoblast differentiation of bone marrow mesenchymal stem cells by suppressing ERK1/2 signaling pathway.

PubMed

Abdallah, Basem M; Alzahrani, Abdullah M; Kassem, Moustapha

2018-05-01

Secreted Clusterin (sCLU, also known as Apolipoprotein J) is an anti-apoptotic glycoprotein involved in the regulation of cell proliferation, lipid transport, extracellular tissue remodeling and apoptosis. sCLU is expressed and secreted by mouse bone marrow-derived skeletal (stromal or mesenchymal) stem cells (mBMSCs), but its functional role in MSC biology is not known. In this study, we demonstrated that Clusterin mRNA expression and protein secretion in conditioned medium increased during adipocyte differentiation and decreased during osteoblast differentiation of mBMSCs. Treatment of mBMSC cultures with recombinant sCLU protein increased cell proliferation and exerted an inhibitory effect on the osteoblast differentiation while stimulated adipocyte differentiation in a dose-dependent manner. siRNA-mediated silencing of Clu expression in mBMSCs reduced adipocyte differentiation and stimulated osteoblast differentiation of mBMSCs. Furthermore, the inhibitory effect of sCLU on the osteoblast differentiation of mBMSCs was mediated by the suppression of extracellular signal-regulated kinase (ERK1/2) phosphorylation. In conclusion, we identified sCLU as a regulator of mBMSCs lineage commitment to osteoblasts versus adipocytes through a mechanism mediated by ERK1/2 signaling. Inhibiting sCLU is a possible therapeutic approach for enhancing osteoblast differentiation and consequently bone formation. Copyright © 2018 Elsevier Inc. All rights reserved.

Alpha-syntrophin deficient mice are protected from adipocyte hypertrophy and ectopic triglyceride deposition in obesity.

PubMed

Eisinger, Kristina; Rein-Fischboeck, Lisa; Neumeier, Markus; Schmidhofer, Sandra; Pohl, Rebekka; Haberl, Elisabeth M; Liebisch, Gerhard; Kopp, Andrea; Schmid, Andreas; Krautbauer, Sabrina; Buechler, Christa

2018-06-01

Alpha-syntrophin (SNTA) is a molecular adapter protein which is expressed in adipocytes. Knock-down of SNTA in 3T3-L1 preadipocytes increases cell proliferation, and differentiated adipocytes display small lipid droplets. These effects are both characteristics of healthy adipose tissue growth which is associated with metabolic improvements in obesity. To evaluate a role of SNTA in adipose tissue morphology and obesity associated metabolic dysfunction, SNTA deficient mice were fed a standard chow or a high fat diet. Mice deficient of SNTA had less fat mass and smaller adipocytes in obesity when compared to control animals. Accordingly, these animals did not develop liver steatosis and did not store excess triglycerides in skeletal muscle upon high fat diet feeding. SNTA-/- animals were protected from hyperinsulinemia and hepatic insulin resistance. Of note, body-weight, food uptake, and serum lipids were normal in the SNTA null mice. SNTA was induced in adipose tissues but not in the liver of diet induced obese and ob/ob mice. In human subcutaneous and visceral fat of seven patients SNTA was similarly expressed and was not associated with body mass index. Current data demonstrate beneficial effects of SNTA deficiency in obesity which is partly attributed to smaller adipocytes and reduced white adipose tissue mass. Higher SNTA protein in fat depots of obese mice may contribute to adipose tissue hypertrophy and ectopic lipid deposition which has to be confirmed in humans. Copyright © 2018 Elsevier Inc. All rights reserved.

Oligopeptide complex for targeted non-viral gene delivery to adipocytes

NASA Astrophysics Data System (ADS)

Won, Young-Wook; Adhikary, Partho Protim; Lim, Kwang Suk; Kim, Hyung Jin; Kim, Jang Kyoung; Kim, Yong-Hee

2014-12-01

Commercial anti-obesity drugs acting in the gastrointestinal tract or the central nervous system have been shown to have limited efficacy and severe side effects. Anti-obesity drug development is thus focusing on targeting adipocytes that store excess fat. Here, we show that an adipocyte-targeting fusion-oligopeptide gene carrier consisting of an adipocyte-targeting sequence and 9-arginine (ATS-9R) selectively transfects mature adipocytes by binding to prohibitin. Injection of ATS-9R into obese mice confirmed specific binding of ATS-9R to fat vasculature, internalization and gene expression in adipocytes. We also constructed a short-hairpin RNA (shRNA) for silencing fatty-acid-binding protein 4 (shFABP4), a key lipid chaperone in fatty-acid uptake and lipid storage in adipocytes. Treatment of obese mice with ATS-9R/shFABP4 led to metabolic recovery and body-weight reduction (>20%). The ATS-9R/shFABP4 oligopeptide complex could prove to be a safe therapeutic approach to regress and treat obesity as well as obesity-induced metabolic syndromes.

Insights into an adipocyte whitening program

PubMed Central

Hill, Bradford G

2015-01-01

White adipose tissue plays a critical role in regulating systemic metabolism and can remodel rapidly in response to changes in nutrient availability. Nevertheless, little is known regarding the metabolic changes occurring in adipocytes during obesity. Our laboratory recently addressed this issue in a commonly used, high-fat-diet mouse model of obesity. We found remarkable changes in adipocyte metabolism that occur prior to infiltration of macrophages in expanding adipose tissue. Results of metabolomic analyses, adipose tissue respirometry, electron microscopy, and expression analyses of key genes and proteins revealed dysregulation of several metabolic pathways, loss of mitochondrial biogenetic capacity, and apparent activation of mitochondrial autophagy which were followed in time by downregulation of numerous mitochondrial proteins important for maintaining oxidative capacity. These findings demonstrate the presence of an adipocyte whitening program that may be critical for regulating adipose tissue remodeling under conditions of chronic nutrient excess. PMID:26167407

Adipocyte Triglyceride Turnover Is Independently Associated With Atherogenic Dyslipidemia

PubMed Central

Frayn, Keith; Bernard, Samuel; Spalding, Kirsty; Arner, Peter

2012-01-01

Background Inappropriate storage of fatty acids as triglycerides in adipocytes and their removal from adipocytes through lipolysis and subsequent oxidation may cause the atherogenic dyslipidemia phenotype of elevated apolipoprotein B levels and subsequent hypertriglyceridemia. We tested whether turnover of triglycerides in fat cells was related to dyslipidemia. Methods and Results The age of triglycerides (reflecting removal) and triglyceride storage in adipocytes was determined under free living conditions by measuring incorporation of atmospheric 14C into these lipids within the adipocytes in 47 women and 26 men with a large interindividual variability in body mass index. Because limited 14C data were available, triglyceride age was also determined in 97 men and 233 women by using an algorithm based on adipocyte lipolysis, body fat content, waist‐to‐hip ratio, and insulin sensitivity. This cohort consisted of nonobese subjects since obesity per se is related to all components in the algorithm. Triglyceride turnover (age and storage) was compared with plasma levels of apolipoproteins and lipids. Plasma levels of apolipoprotein B and triglycerides were positively related to triglyceride age in adipocytes, when measured directly using radiocarbon analyses (r=0.45 to 0.47; P<0.0001). This effect was independent of subject age, waist circumference measures, and insulin sensitivity (partial r=0.29 to 0.45; P from 0.03 to <0.0001). Triglyceride storage showed no independent correlation (partial r=0.02 to 0.11; P=0.42 to 0.91). Algorithm‐based values for adipocyte removal of triglycerides were positively associated with plasma triglycerides and apolipoprotein B (r=0.44 to 0.45; P<0.0001) and (also positively) with the inflammation status of adipose tissue (r=0.39 to 0.47; P<0.05). These correlations were statistically independent of subject age and observed in men and women as well as in lean and overweight subjects when subgroups were examined separately

Premalignant lesions skew spleen cell responses to immune modulation by adipocytes.

PubMed

Vielma, Silvana A; Klein, Richard L; Levingston, Corinne A; Young, M Rita I

2013-05-01

Obesity can promote a chronic inflammatory state and is associated with an increased risk for cancer. Since adipocytes can produce mediators that can regulate conventional immune cells, this study sought to determine if the presence of premalignant oral lesions would skew how immune cells respond to adipocyte-derived mediators to create an environment that may be more favorable for their progression toward cancer. While media conditioned by adipocytes stimulated normal spleen cell production of the T helper (Th) type-1 cytokines interleukin (IL)-2, interferon-γ (IFN-γ), IL-12 and granulocyte-monocyte colony-stimulating factor (GM CSF), media from premalignant lesion cells either blocked or had no added affect on the adipocyte-stimulated Th1 cytokine production. In contrast, media conditioned by premalignant lesion cells exacerbated adipocyte-stimulated spleen cell production of the Th2 cytokines IL-10 and IL-13, although it did not further enhance the adipocyte-stimulated spleen cell production of IL-4 and TGF-β. The premalignant lesion environment also heightened the adipocyte-stimulated spleen cell production of the inflammatory mediators IL 1α, IL-1β, IL-6 and IL-9, although it did not further increase the adipocyte-stimulated production of tumor necrosis factor-α (TNF-α). IL 17 production was unaffected by the adipocyte-derived mediators, but was synergistically triggered by adding media from premalignant lesion cells. These stimulatory effects on spleen cell production of Th2 and inflammatory mediators were not induced in the absence of media conditioned by adipocytes. In contrast, media conditioned by adipocytes did not stimulate production of predominantly monocyte-derived chemokine C-X-C motif ligand (CXCL)9, chemokine C-C motif ligand (CCL)3 or CCL4, although it stimulated production of CCL2 and the predominantly T cell-derived chemokine CCL5, which was the only chemokine whose production was further increased by media from premalignant lesions

14-3-3ζ: A numbers game in adipocyte function?

PubMed Central

Lim, Gareth E.; Johnson, James D.

2016-01-01

ABSTRACT Molecular scaffolds are often viewed as passive signaling molecules that facilitate protein-protein interactions. However, new evidence gained from the use of loss-of-function or gain-of-function models is dispelling this notion. Our own recent discovery of 14-3-3ζ as an essential regulator of adipogenesis highlights the complex roles of this member of the 14-3-3 protein family. Depletion of the 14-3-3ζ isoform affected parallel pathways that drive adipocyte development, including pathways controlling the stability of key adipogenic transcription factors and cell cycle progression. Going beyond adipocyte differentiation, this study opens new avenues of research in the context of metabolism, as 14-3-3ζ binds to a variety of well-established metabolic proteins that harbor its canonical phosphorylation binding motifs. This suggests that 14-3-3ζ may contribute to key metabolic signaling pathways, such as those that facilitate glucose uptake and fatty acid metabolism. Herein, we discuss these novel areas of research, which will undoubtedly shed light onto novel roles of 14-3-3ζ, and perhaps its related family members, on glucose homeostasis. PMID:27386155

Optical visualisation of thermogenesis in stimulated single-cell brown adipocytes.

PubMed

Kriszt, Rókus; Arai, Satoshi; Itoh, Hideki; Lee, Michelle H; Goralczyk, Anna G; Ang, Xiu Min; Cypess, Aaron M; White, Andrew P; Shamsi, Farnaz; Xue, Ruidan; Lee, Jung Yeol; Lee, Sung-Chan; Hou, Yanyan; Kitaguchi, Tetsuya; Sudhaharan, Thankiah; Ishiwata, Shin'ichi; Lane, E Birgitte; Chang, Young-Tae; Tseng, Yu-Hua; Suzuki, Madoka; Raghunath, Michael

2017-05-03

The identification of brown adipose deposits in adults has led to significant interest in targeting this metabolically active tissue for treatment of obesity and diabetes. Improved methods for the direct measurement of heat production as the signature function of brown adipocytes (BAs), particularly at the single cell level, would be of substantial benefit to these ongoing efforts. Here, we report the first application of a small molecule-type thermosensitive fluorescent dye, ERthermAC, to monitor thermogenesis in BAs derived from murine brown fat precursors and in human brown fat cells differentiated from human neck brown preadipocytes. ERthermAC accumulated in the endoplasmic reticulum of BAs and displayed a marked change in fluorescence intensity in response to adrenergic stimulation of cells, which corresponded to temperature change. ERthermAC fluorescence intensity profiles were congruent with mitochondrial depolarisation events visualised by the JC-1 probe. Moreover, the averaged fluorescence intensity changes across a population of cells correlated well with dynamic changes such as thermal power, oxygen consumption, and extracellular acidification rates. These findings suggest ERthermAC as a promising new tool for studying thermogenic function in brown adipocytes of both murine and human origins.

Obesity in mice with adipocyte-specific deletion of clock component Arntl

PubMed Central

Paschos, Georgios K; Ibrahim, Salam; Song, Wen-Liang; Kunieda, Takeshige; Grant, Gregory; Reyes, Teresa M; Bradfield, Christopher A; Vaughan, Cheryl H; Eiden, Michael; Masoodi, Mojgan; Griffin, Julian L; Wang, Fenfen; Lawson, John A; FitzGerald, Garret A

2013-01-01

Adipocytes store excess energy in the form of triglycerides and signal the levels of stored energy to the brain. Here we show that adipocyte-specific deletion of Arntl (also known as Bmal1), a gene encoding a core molecular clock component, results in obesity in mice with a shift in the diurnal rhythm of food intake, a result that is not seen when the gene is disrupted in hepatocytes or pancreatic islets. Changes in the expression of hypothalamic neuropeptides that regulate appetite are consistent with feedback from the adipocyte to the central nervous system to time feeding behavior. Ablation of the adipocyte clock is associated with a reduced number of polyunsaturated fatty acids in adipocyte triglycerides. This difference between mutant and wild-type mice is reflected in the circulating concentrations of polyunsaturated fatty acids and nonesterified polyunsaturated fatty acids in hypothalamic neurons that regulate food intake. Thus, this study reveals a role for the adipocyte clock in the temporal organization of energy regulation, highlights timing as a modulator of the adipocyte-hypothalamic axis and shows the impact of timing of food intake on body weight. PMID:23142819

Crosstalk between EET and HO-1 downregulates Bach1 and adipogenic marker expression in mesenchymal stem cell derived adipocytes

PubMed Central

Vanella, Luca; Kim, Dong Hyun; Sodhi, Komal; Barbagallo, Ignazio; Burgess, Angela P.; Falck, John R.; Schwartzman, Michal L.; Abraham, Nader G.

2013-01-01

Epoxygenase activity and synthesis of epoxyeicosatrienoic acids (EETs) have emerged as important modulators of obesity and diabetes. We examined the effect of the EET-agonist 12-(3-hexylureido)dodec-8(2) enoic acid on mesenchymal stem cell (MSC) derived adipocytes proliferation and differentiation. MSCs expressed substantial levels of EETs and inhibition of soluble epoxide hydrolase (sEH) increased the level of EETs and decreased adipogenesis. EET agonist treatment increased HO-1 expression by inhibiting a negative regulator of HO-1 expression, Bach-1. EET treatment also increased βcatenin and pACC levels while decreasing PPARγ C/EBPα and fatty acid synthase levels. These changes were manifested by a decrease in the number of large inflammatory adipocytes, TNFα, IFNγ and IL-1α, but an increase in small adipocytes and in adiponectin levels. In summary, EET agonist treatment inhibits adipogenesis and decreases the levels of inflammatory cytokines suggesting the potential action of EETs as intracellular lipid signaling modulators of adipogenesis and adiponectin. PMID:21821145

MyomiR-133 regulates brown fat differentiation through Prdm16.

PubMed

Trajkovski, Mirko; Ahmed, Kashan; Esau, Christine C; Stoffel, Markus

2012-12-01

Brown adipose tissue (BAT) uses the chemical energy of lipids and glucose to produce heat, a function that can be induced by cold exposure or diet. A key regulator of BAT is the gene encoding PR domain containing 16 (Prdm16), whose expression can drive differentiation of myogenic and white fat precursors to brown adipocytes. Here we show that after cold exposure, the muscle-enriched miRNA-133 is markedly downregulated in BAT and subcutaneous white adipose tissue (SAT) as a result of decreased expression of its transcriptional regulator Mef2. miR-133 directly targets and negatively regulates PRDM16, and inhibition of miR-133 or Mef2 promotes differentiation of precursors from BAT and SAT to mature brown adipocytes, thereby leading to increased mitochondrial activity. Forced expression of miR-133 in brown adipogenic conditions prevents the differentiation to brown adipocytes in both BAT and SAT precursors. Our results point to Mef2 and miR-133 as central upstream regulators of Prdm16 and hence of brown adipogenesis in response to cold exposure in BAT and SAT.

Coupled 182W-142Nd constraint for early Earth differentiation

PubMed Central

Moynier, Frederic; Yin, Qing-Zhu; Irisawa, Keita; Boyet, Maud; Jacobsen, Benjamin; Rosing, Minik T.

2010-01-01

Recent high precision 142Nd isotope measurements showed that global silicate differentiation may have occurred as early as 30–75 Myr after the Solar System formation [Bennett V, et al. (2007) Science 318:1907–1910]. This time scale is almost contemporaneous with Earth’s core formation at ∼30 Myr [Yin Q, et al. (2002) Nature 418:949–952]. The 182Hf-182W system provides a powerful complement to the 142Nd results for early silicate differentiation, because both core formation and silicate differentiation fractionate Hf from W. Here we show that eleven terrestrial samples from diverse tectonic settings, including five early Archean samples from Isua, Greenland, of which three have been previously shown with 142Nd anomalies, all have a homogeneous W isotopic composition, which is ∼2ε-unit more radiogenic than the chondritic value. By using a 3-stage model calculation that describes the isotopic evolution in chondritic reservoir and core segregation, as well as silicate differentiation, we show that the W isotopic composition of terrestrial samples provides the most stringent time constraint for early core formation (27.5–38 Myr) followed by early terrestrial silicate differentiation (38–75 Myr) that is consistent with the terrestrial 142Nd anomalies. PMID:20534492

Interleukin-17A Differentially Induces Inflammatory and Metabolic Gene Expression in the Adipose Tissues of Lean and Obese Mice

PubMed Central

Qu, Yine; Zhang, Qiuyang; Ma, Siqi; Liu, Sen; Chen, Zhiquan; Mo, Zhongfu; You, Zongbing

2016-01-01

The functions of interleukin-17A (IL-17A) in adipose tissues and adipocytes have not been well understood. In the present study, male mice were fed with a regular diet (n = 6, lean mice) or a high-fat diet (n = 6, obese mice) for 30 weeks. Subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) were analyzed for IL-17A levels. SAT and VAT were treated with IL-17A and analyzed for inflammatory and metabolic gene expression. Mouse 3T3-L1 pre-adipocytes were differentiated into adipocytes, followed with IL-17A treatment and analysis for inflammatory and metabolic gene expression. We found that IL-17A levels were higher in obese SAT than lean SAT; the basal expression of inflammatory and metabolic genes was different between SAT and VAT and between lean and obese adipose tissues. IL-17A differentially induced expression of inflammatory and metabolic genes, such as tumor necrosis factor α, Il-6, Il-1β, leptin, and glucose transporter 4, in adipose tissues of lean and obese mice. IL-17A also differentially induced expression of inflammatory and metabolic genes in pre-adipocytes and adipocytes, and IL-17A selectively activated signaling pathways in adipose tissues and adipocytes. These findings suggest that IL-17A differentially induces inflammatory and metabolic gene expression in the adipose tissues of lean and obese mice. PMID:27070576

Simple Analysis of Lipid Inhibition Activity on an Adipocyte Micro-Cell Pattern Chip.

PubMed

Kim, Gi Yong; Yeom, Su-Jin; Jang, Sung-Chan; Lee, Chang-Soo; Roh, Changhyun; Jeong, Heon-Ho

2018-06-04

Polydimethyl-siloxane (PDMS) is often applied to fabricate cell chips. In this study, we fabricated an adipocyte microcell pattern chips using PDMS to analyze the inhibition activity of lipid droplets in mouse embryo fibroblast cells (3T3-L1) with anti-obesity agents. To form the PDMS based micropattern, we applied the micro-contact printing technique using PDMS micro-stamps that had been fabricated by conventional soft lithography. This PDMS micro-pattern enabled the selective growth of 3T3-L1 cells onto the specific region by preventing cell adhesion on the PDMS region. It then allowed growth of the 3T3-L1 cells in the chip for 10 days and confirmed that lipid droplets were formed in the 3T3-L1 cells. After treatment of orlistat and quercetin were treated in an adipocyte micro-cell pattern chip with 3T3-L1 cells for six days, we found that orlistat and quercetin exhibited fat inhibition capacities of 19.3% and 24.4% from 0.2 μM of lipid droplets in 3T3-L1 cells. In addition, we conducted a direct quantitative analysis of 3T3-L1 cell differentiation using Oil Red O staining. In conclusion, PDMS-based adipocyte micro-cell pattern chips may contribute to the development of novel bioactive compounds.

Simvastatin inhibits ox-LDL-induced inflammatory adipokines secretion via amelioration of ER stress in 3T3-L1 adipocyte.

PubMed

Wu, Zhi-hong; Chen, Ya-qin; Zhao, Shui-ping

2013-03-08

Adipocytes behave as a rich source of pro-inflammatory cytokines including tumor necrosis factor-α (TNF-α) and monocyte chemoattractant protein 1 (MCP-1). Endoplasmic reticulum (ER) stress in adipocytes can alter adipokines secretion and induce inflammation. The aim of this study is to evaluate the effect of simvastatin on the ox-LDL-induced ER stress and expression and secretion of TNF-α and MCP-1 in 3T3-L1 adipocytes. Differentiated adipocytes were treated with various concentrations of ox-LDL (0-100 μg/ml) for 24h with or without simvastatin pre-treatment. The protein expressions of ER stress markers, glucose-regulated protein 78 (GRP78) and C/EBP homology protein (CHOP), were determined by Western blot analysis. The mRNA expressions of TNF-α and MCP-1 were measured by real-time PCR. The protein release of TNF-α and MCP-1 in culture medium were evaluated by ELISA. Ox-LDL treatment led to significant up-regulation of GRP78 and CHOP in dose-dependent manner. The expressions of TNF-α and MCP-1 were dose-dependently increased at mRNA and protein levels after ox-LDL intervention. The effects of ox-LDL on adipocytes were abolished by pre-treatment with 4-phenylbutyrate (4-PBA), a chemical chaperone known to ameliorate ER stress. Simvastatin could inhibit ox-LDL-induced ER stress and reduce the expression of TNF-α and MCP-1 at mRNA and protien level in dose dependent manner. In conclusion, ox-LDL can stimulate the expression and secretion of TNF-α and MCP-1 through its activation of ER stress in adipocytes. Simvastatin might exert direct anti-inflammatory effects in adipocytes through amelioration of ER stress. Copyright © 2013 Elsevier Inc. All rights reserved.

Pulicaria jaubertii E. Gamal-Eldin reduces triacylglyceride content and modifies cellular antioxidant pathways in 3T3-L1 adipocytes

USDA-ARS?s Scientific Manuscript database

Currently, levels of obesity in Middle Eastern countries are increasing. Phytochemicals have anti-obesogenic properties as evidenced by prevention of adipocyte differentiation. In Yemen, Pulicaria jaubertii E.Gamal-Eldin (PJ) is a food additive and a traditional medicine. We evaluated the ability of...

MicroRNA-204-5p regulates 3T3-L1 preadipocyte proliferation, apoptosis and differentiation.

PubMed

Du, Jingjing; Zhang, Peiwen; Gan, Mailin; Zhao, Xue; Xu, Yan; Li, Qiang; Jiang, Yanzhi; Tang, Guoqing; Li, Mingzhou; Wang, Jinyong; Li, Xuewei; Zhang, Shunhua; Zhu, Li

2018-08-20

Obesity due to excessive lipid accumulation is closely associated with metabolic diseases such as type 2 diabetes, insulin resistance and inflammation. Therefore, a detailed understanding of the molecular mechanisms that underlie adipogenesis is crucial to develop treatments for diseases related to obesity. Here, we found that the microRNA-204-5p (miR-204-5p) was expressed at low levels in fat tissues from obese mice fed long-term with a high-fat diet (HFD). Overexpression or inhibition of miR-204-5p in vitro in 3T3-L1 preadipocytes significantly inhibited or promoted 3T3-L1 proliferation, respectively, an effect mediated by regulating cell proliferation factors. miR-204-5p also induced preadipocyte apoptosis by directly targeting the 3' UTR region of Bcl-2, reducing the constitutive suppression of Bcl-2 on p53-dependent apoptosis. Interestingly, overexpression of miR-204-5p during adipocyte differentiation significantly increased the number of oil red O+ cells, triglyceride accumulation and the expression of markers associated with adipocyte differentiation. In contrast, inhibition of miR-204-5p had the opposite effect on 3T3-L1 adipocyte differentiation. Luciferase activity assays and qRT-PCR showed that miR-204-5p regulates adipocyte differentiation by negatively regulating KLF3, a negative regulator of lipogenesis. Taken together, our findings showed that miR-204-5p inhibits proliferation and induces apoptosis of preadipocytes by regulating Bcl-2, but also promotes adipocyte differentiation by targeting KLF3. Copyright © 2018. Published by Elsevier B.V.

Data on regulation of the gene for the adipocyte-enriched micropeptide Adig/Smaf1 by qPCR analysis and luciferase reporter assay.

PubMed

Ren, Gang; Cairl, Nicholas; Kim, Ji Young; Smas, Cynthia M

2016-12-01

This article describes qPCR analysis for the Adig/Smaf1 gene in multiple in vitro adipocyte differentiation models including white and brown adipogenesis, cell lines and primary cultures. The article also contains qPCR data for transcript levels of Adig/Smaf1 in a wide panel of murine tissues. Expression of Adig/Smaf1 transcript in white and brown adipose tissue in fasted and refed mice is reported and also data for Adig/Smaf1 transcript expression in genetically obese ob/ob mice. Data on the effects of siRNA-mediated knockdown of Srebp1c on Adig/Smaf1 transcript levels in 3T3-L1 adipocytes are shown. Luciferase reporter assays provide data for regulation of an ~ 2 kb fragment of the 5' flanking region of Adig/Smaf1 gene by PPARγ/RXRα. This data is related to a research article describing Adig/Smaf1 protein expression, "Expression, regulation and functional assessment of the 80 amino acid Small Adipocyte Factor 1 (Smaf1) protein in adipocytes" (G. Ren, P. Eskandari, S. Wang, C.M. Smas, 2016) [1].

Temperature induced modulation of lipid oxidation and lipid accumulation in palmitate-mediated 3T3-L1 adipocytes and 3T3-L1 adipocytes.

PubMed

Lin, Xiaofen; Li, Yi; Leung, Polly Hangmei; Li, Jiashen; Hu, Junyan; Liu, Xuan; Li, Zhi

2016-05-01

Human skin temperature can vary widely depending on anatomical location and ambient temperature. It is also known that local changes in skin and subcutaneous temperature can affect fat metabolism. This study aimed to explore the potential effects of surrounding thermal environment on fat by investigating cell viability, lipid oxidation, and lipid accumulation in 3T3-L1 adipocytes and palmitate-treated adipocytes after 4h incubation. No significant differences of viability in 3T3-L1 adipocytes were detected under different temperature conditions. Despite no significant increase being observed under warm temperature (39°C) conditions, a similarly significant suppression of intracellular reactive oxygen species (ROS) and lipid peroxidation were found in 3T3-L1 adipocytes and palmitate-treated adipocytes under 4h exposure to cooler temperatures of 31-33°C (P<0.01). ROS, chemically reactive molecules containing oxygen, are currently understood to be a major contributor to oxidantive stress in obesity. Additionally, cooler temperatures (31-33°C) could improve the size of lipid droplets in 3T3-L1 adipocytes (P<0.01), but no significant effect was generated by temperature change on lipid droplets in palmitate-treated adipocytes. In the palmitate-induced adiposity model, although excessive ROS and lipid peroxidation has been attenuated by temperature decrease (P<0.01), it still does not positively modulate lipid droplet size (P>0.05) and remedy the palmitate damage induced cell death (P<0.01). These findings provide preliminary support for potential interventions based on temperature manipulation for cell metabolism of adipocytes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Transcriptional targets in adipocyte biology

PubMed Central

Rosen, Evan; Eguchi, Jun; Xu, Zhao

2010-01-01

The global burden of metabolic disease demands that we develop new therapeutic strategies. Many of these approaches may center on manipulating the behavior of adipocytes, which contribute directly and indirectly to a host of disease processes including obesity and type 2 diabetes. One way to achieve this goal will be to alter key transcriptional pathways in fat cells, such as those regulating glucose uptake, lipid handling, or adipokine secretion. In this review we look at what is known about how adipocytes govern their physiology at the gene expression level, and we discuss novel ways that we can accelerate our understanding of this area. PMID:19534570

Peroxisome proliferator-activated receptor gamma modulation and lipogenic response in adipocytes of small-for-gestational age offspring

PubMed Central

2012-01-01

resistance to BADGE treatment. Conclusions SGA adipocytes exhibit an enhanced adipogenic and lipogenic potential in early postnatal life. By p21, SGA demonstrated resistance to PPARγ repressor-ligand treatment, and selective response to high dose PPARγ activator-ligand treatment in adipogenic and lipogenic gene expression. p21 SGA adipocytes revealed increased fatty acid de novo synthesis through a complex relationship with glucose metabolism. PMID:22726273

Mangiferin ameliorates insulin resistance by inhibiting inflammation and regulatiing adipokine expression in adipocytes under hypoxic condition.

PubMed

Yang, Chao-Qiang; Xu, Jing-Hua; Yan, Dan-Dan; Liu, Bao-Lin; Liu, Kang; Huang, Fang

2017-09-01

Adipose tissue hypoxia has been recognized as the initiation of insulin resistance syndromes. The aim of the present study was to investigate the effects of mangiferin on the insulin signaling pathway and explore whether mangiferin could ameliorate insulin resistance caused by hypoxia in adipose tissue. Differentiated 3T3-L1 adipocytes were incubated under normal and hypoxic conditions, respectively. Protein expressions were analyzed by Western blotting. Inflammatory cytokines and HIF-1-dependent genes were tested by ELISA and q-PCR, respectively. The glucose uptake was detected by fluorescence microscopy. HIF-1α was abundantly expressed during 8 h of hypoxic incubation. Inflammatory reaction was activated by up-regulated NF-κB phosphorylation and released cytokines like IL-6 and TNF-α. Glucose uptake was inhibited and insulin signaling pathway was damaged as well. Mangiferin substantially inhibited the expression of HIF-1α. Lactate acid and lipolysis, products released by glycometabolism and lipolysis, were also inhibited. The expression of inflammatory cytokines was significantly reduced and the damaged insulin signaling pathway was restored to proper functional level. The glucose uptake of hypoxic adipocytes was promoted and the dysfunction of adipocytes was relieved. These results showed that mangiferin could not only improve the damaged insulin signaling pathway in hypoxic adipocytes, but also ameliorate inflammatory reaction and insulin resistance caused by hypoxia. Copyright © 2017 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

[PRODUCT OF THE BMI1--A KEY COMPONENT OF POLYCOMB--POSITIVELY REGULATES ADIPOCYTE DIFFERENTIATION OF MOUSE MESENCHYMAL STEM CELLS].

PubMed

Petrov, N S; Vereschagina, N A; Sushilova, E N; Kropotov, A V; Miheeva, N F; Popov, B V

2016-01-01

Bmil is a key component of Polycomb (PcG), which in mammals controls the basic functions of mammalian somatic stem cells (SSC) such as self-renewal and differentiation. Bmi1 supports SSC via transcriptional suppression of genes associated with cell cycle and differentiation. The most studied target genes of Bmi1 are the genes of Ink4 locus, CdkI p16(Ink4a) and p1(Arf), suppression of which due to activating mutations of the BMI1 results in formation of cancer stem cells (CSC) and carcinomas in various tissues. In contrast, inactivation of BMI1 results in cell cycle arrest and cell senescence. Although clinical phenomena of hypo- and hyperactivation of BMI1 are well known, its targets and mechanisms of regulation of tissue specific SSC are still obscure. The goal of this study was to evaluate the regulatory role of BMI1 in adipocyte differentiation (AD) of mouse mesenchymal stem cells (MSC). Induction of AD in mouse MSC of the C3H10T1/2 cell line was associated with an increase in the expression levels of BMI1, the genes of pRb family (RB, p130) and demethylase UTX, but not methyltransferase EZH2, whose products regulate the methylation levels of H3K27. It was observed earlier that H3K27me3 may play the role of the epigenetic switch by promoting AD of human MSC via activating expression of the PPARγ2, the master gene of AD (Hemming et al., 2014). Here we show that inactivation of BMI1 using specific siRNA slows and decreases the levels of AD, but does not abolish it. This is associated with a complete inhibition of the expression of adipogenic marker genes--PPARγ2, ADIPOQ and a decrease in the expression of RB, p130, but not UTX. The results obtained give evidence that the epigenetic mechanism regulating AD differentiation in mouse and human MSC is different.

Purple corn silk: A potential anti-obesity agent with inhibition on adipogenesis and induction on lipolysis and apoptosis in adipocytes.

PubMed

Chaiittianan, Rungsiri; Sutthanut, Khaetthareeya; Rattanathongkom, Ariya

2017-04-06

Corn silk or the stigma of Zea mays L. has traditionally been used in weight loss stimulation and treatment of cystitis, urinary infections and obesity. Purple corn silk, rich of polyphenolic substances, was reported on anti-diabetic and anti-obesity effect in animal studies. However, scientific evidence on mechanisms and targets of action of purple corn silk related to adipocyte life cycle has been limited. To determine phytochemical compositions and investigate anti-obesity potential of the purple corn silk focusing on interruption of adipocyte life cycle; effect on pre-adipocyte proliferation, adipogenesis, adipocyte lipolysis, and apoptosis. The ethanolic purple corn silk extract (PCS) was prepared and investigated for phytochemical compositions by LC/MS/MS technique and anti-obesity potential using murine 3T3-L1 cell line. Using methyl thiazole tetrazolium (MTT) assay, the effects on pre-adipocytes and adipocyte viability and on pre-adipocytes proliferation at 24-, 48-, and 72-h incubation period were evaluated. In addition, anti-adipogenesis via inhibition on adipocyte differentiation and reduction of total lipid accumulation was evaluated using Oil Red O staining and spectrophotometric methods, respectively. The lipolysis effect was determined by measurement of glycerol released content using glycerol test kit after 48-h treatment of PCS to adipocytes. Apoptosis inductive effect was done by using 2-(4-Amidinophenyl)-6-indolecarbamidine dihydrochloride (DAPI) staining method. The polyphenols including anthocyanins, quercetin and phenolic acids and derivatives were found as the major chemical compositions of the PCS. With multiple-stages interruption on the adipocyte life cycle, anti-obesity effect of PCS was interestingly demonstrated. When compared to the control, the PCS at concentration range between 250-1000 μg/mL showed anti-adipogenesis effect as expressing of significant inhibition on pre-adipocyte proliferation at all incubation period (43.52±5

Adiponectin may be a biomarker of early atherosclerosis of smokers and decreased by nicotine through KATP channel in adipocytes.

PubMed

Fan, Li Hong; He, Ying; Xu, Wei; Tian, Hong Yan; Zhou, Yan; Liang, Qi; Huang, Xin; Huo, Jian Hua; Li, Hong Bin; Bai, Ling; Ma, Ai Qun

2015-01-01

Plasm adiponectin is decreased in smokers. Adiponectin is emerging as a potential key molecular marker in atherosclerosis and other cardiovascular diseases. The aim of this study was to investigate the association between serum adiponectin levels and early atherosclerosis in smokers. Furthermore, the role of the KATP channel in the down-regulation of adiponectin by smoking was preliminarily explored. We consecutively enrolled 96 men, including 50 smokers with atherosclerosis and 46 nonsmokers. Serum adiponectin was detected with enzyme-linked immunosorbent assay - in all participants. Large (C1) and small (C2) artery elasticity indices and carotid intima-media thickness (IMT) were measured as evaluation indexes of early atherosclerosis in smokers. Finally, the effect of nicotine via ATP-dependent potassium (KATP) channels on adiponectin secretion by 3T3-L1 preadipocytes was examined in vitro. Adiponectin levels of smokers were statistically negatively correlated to IMT (r = -.440; P < 0.001) and positively correlated to C1 (r = 0.448; P < 0.001) as well as C2 (r = 0.426; P = 0.002). In 3-T3-L1 preadipocytes, nicotine treatment significantly decreased adiponectin levels (P = 0.003), whereas the adiponectin level was rescued by the inhibition of KATP channel (P < 0.001). Serum adiponectin level was an independent predictor of early atherosclerosis in smokers. Nicotine might decrease adiponectin in part through altering KATP channels in adipocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

Leptin differentially regulates STAT3 activation in the ob/ob mice adipose mesenchymal stem cells

USDA-ARS?s Scientific Manuscript database

Leptin-deficient genetically obese ob/ob mice exhibit adipocyte hypertrophy and hyperplasia as well as elevated adipose tissue and systemic inflammation. Studies have shown that multipotent stem cells isolated from adult adipose tissue can differentiate into adipocytes ex vivo and thereby contribute...

Fatty acid-induced mitochondrial uncoupling in adipocytes is not a promising target for treatment of insulin resistance unless adipocyte oxidative capacity is increased.

PubMed

Frayn, K N; Langin, D; Karpe, F

2008-03-01

The release of fatty acids from white adipose tissue is regulated at several levels. We have examined the suggestion that fatty acid release might be diminished by upregulation of mitochondrial fatty acid oxidation in the adipocyte, through increasing mitochondrial uncoupling. The intrinsic oxidative capacity of white adipose tissue is low, and older studies suggest that there is little fatty acid oxidation in white adipocytes, human or rodent. We have examined data on fatty acid metabolism and O(2) consumption in human white adipose tissue in vivo, and conclude that increasing fatty acid oxidation within the oxidative capacity of the tissue would produce only small changes (a few percent) in fatty acid release. The major locus of control of fatty acid release beyond the stimulation of lipolysis is the pathway of fatty acid esterification, already probably targeted by the thiazolidinedione insulin-sensitising agents. An alternative approach would be to upregulate the mitochondrial capacity of the adipocyte. We review proof-of-concept studies in which the phenotype of the white adipocyte has been changed to resemble that of the brown adipocyte by expression of peroxisome proliferator-activated receptor coactivator-1alpha. This increases oxidative capacity and also leads to fatty acid retention through upregulation of glycerol-3-phosphate production, and hence increased fatty acid re-esterification. We conclude that prevention or treatment of insulin resistance through alteration of adipocyte fatty acid handling will require more than a simple alteration of the activity of mitochondrial beta-oxidation within normal limits.

Postlipolytic insulin-dependent remodeling of micro lipid droplets in adipocytes

PubMed Central

Ariotti, Nicholas; Murphy, Samantha; Hamilton, Nicholas A.; Wu, Lizhen; Green, Kathryn; Schieber, Nicole L.; Li, Peng; Martin, Sally; Parton, Robert G.

2012-01-01

Despite the lipolysis–lipogenesis cycle being a fundamental process in adipocyte biology, very little is known about the morphological changes that occur during this process. The remodeling of lipid droplets to form micro lipid droplets (mLDs) is a striking feature of lipolysis in adipocytes, but once lipolysis ceases, the cell must regain its basal morphology. We characterized mLD formation in cultured adipocytes, and in primary adipocytes isolated from mouse epididymal fat pads, in response to acute activation of lipolysis. Using real-time quantitative imaging and electron tomography, we show that formation of mLDs in cultured adipocytes occurs throughout the cell to increase total LD surface area by ∼30% but does not involve detectable fission from large LDs. Peripheral mLDs are monolayered structures with a neutral lipid core and are sites of active lipolysis. Electron tomography reveals preferential association of mLDs with the endoplasmic reticulum. Treatment with insulin and fatty acids results in the reformation of macroLDs and return to the basal state. Insulin-dependent reformation of large LDs involves two distinct processes: microtubule-dependent homotypic fusion of mLDs and expansion of individual mLDs. We identify a physiologically important role for LD fusion that is involved in a reversible lipolytic cycle in adipocytes. PMID:22456503

Bone marrow adipocytes as negative regulators of the hematopoietic microenvironment

PubMed Central

Naveiras, Olaia; Nardi, Valentina; Wenzel, Pamela L.; Fahey, Frederic; Daley, George Q.

2009-01-01

Osteoblasts and endothelium constitute functional niches that support hematopoietic stem cells (HSC) in mammalian bone marrow (BM) 1,2,3 . Adult BM also contains adipocytes, whose numbers correlate inversely with the hematopoietic activity of the marrow. Fatty infiltration of hematopoietic red marrow follows irradiation or chemotherapy and is a diagnostic feature in biopsies from patients with marrow aplasia 4. To explore whether adipocytes influence hematopoiesis or simply fill marrow space, we compared the hematopoietic activity of distinct regions of the mouse skeleton that differ in adiposity. By flow cytometry, colony forming activity, and competitive repopulation assay, HSCs and short-term progenitors are reduced in frequency in the adipocyte-rich vertebrae of the mouse tail relative to the adipocyte-free vertebrae of the thorax. In lipoatrophic A-ZIP/F1 “fatless” mice, which are genetically incapable of forming adipocytes8, and in mice treated with the PPARγ inhibitor Bisphenol-A-DiGlycidyl-Ether (BADGE), which inhibits adipogenesis9, post-irradiation marrow engraftment is accelerated relative to wild type or untreated mice. These data implicate adipocytes as predominantly negative regulators of the bone marrow microenvironment, and suggest that antagonizingmarrow adipogenesis may enhance hematopoietic recovery in clinical bone marrow transplantation. PMID:19516257

Target molecules in 3T3-L1 adipocytes differentiation are regulated by maslinic acid, a natural triterpene from Olea europaea.

PubMed

Pérez-Jiménez, Amalia; Rufino-Palomares, Eva E; Fernández-Gallego, Nieves; Ortuño-Costela, M Carmen; Reyes-Zurita, Fernando J; Peragón, Juan; García-Salguero, Leticia; Mokhtari, Khalida; Medina, Pedro P; Lupiáñez, José A

2016-11-15

Metabolic syndrome is a set of pathologies among which stand out the obesity, which is related to the lipid droplet accumulation and changes to cellular morphology regulated by several molecules and transcription factors. Maslinic acid (MA) is a natural product with demonstrated pharmacological functions including anti-inflammation, anti-tumor and anti-oxidation, among others. Here we report the effects of MA on the adipogenesis process in 3T3-L1 cells. Cell viability, glucose uptake, cytoplasmic triglyceride droplets, triglycerides quantification, gene transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ) and adipocyte fatty acid-binding protein (aP2) and intracellular Ca 2+ levels were determined in pre-adipocytes and adipocytes of 3T3-L1 cells. MA increased glucose uptake. MA also decreased lipid droplets and triglyceride levels, which is in concordance with the down-regulation of PPARγ and aP2. Finally, MA increased the intracellular Ca 2+ concentration, which could also be involved in the demonstrated antiadipogenic effect of this triterpene. MA has been demonstrated as potential antiadipogenic compound in 3T3-L1 cells. Copyright © 2016 Elsevier GmbH. All rights reserved.

Human Mature Adipocytes Express Albumin and This Expression Is Not Regulated by Inflammation

PubMed Central

Sirico, Maria Luisa; Guida, Bruna; Procino, Alfredo; Pota, Andrea; Sodo, Maurizio; Grandaliano, Giuseppe; Simone, Simona; Pertosa, Giovanni; Riccio, Eleonora; Memoli, Bruno

2012-01-01

Aims. Our group investigated albumin gene expression in human adipocytes, its regulation by inflammation and the possible contribution of adipose tissue to albumin circulating levels. Methods. Both inflamed and healthy subjects provided adipose tissue samples. RT-PCR, Real-Time PCR, and Western Blot analysis on homogenates of adipocytes and pre-adipocytes were performed. In sixty-three healthy subjects and fifty-four micro-inflamed end stage renal disease (ESRD) patients circulating levels of albumin were measured by nephelometry; all subjects were also evaluated for body composition, calculated from bioelectrical measurements and an thropometric data. Results. A clear gene expression of albumin was showed in pre-adipocytes and, for the first time, in mature adipocytes. Albumin gene expression resulted significantly higher in pre-adipocytes than in adipocytes. No significant difference in albumin gene expression was showed between healthy controls and inflamed patients. A significant negative correlation was observed between albumin levels and fat mass in both healthy subjects and inflamed ESRD patients. Conclusions. In the present study we found first time evidence that human adipocytes express albumin. Our results also showed that systemic inflammation does not modulate albumin gene expression. The negative correlation between albumin and fat mass seems to exclude a significant contributing role of adipocyte in plasma albumin. PMID:22675238

Extracellular Vesicles from Hypoxic Adipocytes and Obese Subjects Reduce Insulin‐Stimulated Glucose Uptake

PubMed Central

Mleczko, Justyna; Ortega, Francisco J.; Falcon‐Perez, Juan Manuel; Wabitsch, Martin; Fernandez‐Real, Jose Manuel

2018-01-01

Scope We investigate the effects of extracellular vesicles (EVs) obtained from in vitro adipocyte cell models and from obese subjects on glucose transport and insulin responsiveness. Methods and results EVs are isolated from the culture supernatant of adipocytes cultured under normoxia, hypoxia (1% oxygen), or exposed to macrophage conditioned media (15% v/v). EVs are isolated from the plasma of lean individuals and subjects with obesity. Cultured adipocytes are incubated with EVs and activation of insulin signalling cascades and insulin‐stimulated glucose transport are measured. EVs released from hypoxic adipocytes impair insulin‐stimulated 2‐deoxyglucose uptake and reduce insulin mediated phosphorylation of AKT. Insulin‐mediated phosphorylation of extracellular regulated kinases (ERK1/2) is not affected. EVs from individuals with obesity decrease insulin stimulated 2‐deoxyglucose uptake in adipocytes (p = 0.0159). Conclusion EVs released by stressed adipocytes impair insulin action in neighboring adipocytes. PMID:29292863

Relationship of Adipocyte Size with Adiposity and Metabolic Risk Factors in Asian Indians

PubMed Central

Meena, Ved Prakash; Seenu, V.; Sharma, M. C.; Mallick, Saumya Ranjan; Bhalla, Ashu Seith; Gupta, Nandita; Mohan, Anant; Guleria, Randeep; Pandey, Ravindra M.; Luthra, Kalpana; Vikram, Naval K.

2014-01-01

Background Enlargement of adipocyte is associated with their dysfunction and alterations in metabolic functions. Objectives We evaluated the association of adipocyte size of subcutaneous and omental adipose tissue with body composition and cardiovascular risk factors in Asian Indians. Methodology Eighty (40 males and 40 females) non-diabetic adult subjects undergoing elective abdominal surgery were included. Pre-surgery evaluation included anthropometric measurements, % body fat by bioimpedance, abdominal fat area at L2–3 level (computed tomography) and biochemical investigations (fasting blood glucose and insulin, lipids and hsCRP). During surgery, about 5 grams each of omental and subcutaneous adipose tissue was obtained for adipocyte size determination. Results Females had higher BMI, % body fat, skinfold thickness, total and subcutaneous abdominal fat area as compared to males. Overweight was present in 42.5% and 67.5%, and abdominal obesity in 5% and 52.5% males and females, respectively. Subcutaneous adipocyte size was significantly higher than omental adipocyte size. Omental adipocyte size correlated more strongly than subcutaneous adipocyte size with measures of adiposity (BMI, waist circumference, %BF), total and subcutaneous abdominal fat area and biochemical measures (fasting glucose, total cholesterol, triglycerides and HOMA-IR), the correlations being stronger in females. The correlation of adipocyte size with metabolic parameters was attenuated after adjusting for measures of adiposity. Conclusion Omental adipocyte size, though smaller than the subcutaneous adipocyte size, was more closely related to measures of adiposity and metabolic parameters. However, the relationship was not independent of measures of adiposity. PMID:25251402

The perfect storm: obesity, adipocyte dysfunction, and metabolic consequences.

PubMed

de Ferranti, Sarah; Mozaffarian, Dariush

2008-06-01

As the prevalence of adiposity soars in both developed and developing nations, appreciation of the close links between obesity and disease increases. The strong relationships between excess adipose tissue and poor health outcomes, including cardiovascular disease, diabetes, and cancer, mandate elucidation of the complex cellular, hormonal, and molecular pathophysiology whereby adiposity initiates and maintains adverse health effects. In this report we review adipocyte metabolism and function in the context of energy imbalance and postprandial nutrient excess, including adipocyte hypertrophy and hyperplasia, adipocyte dysfunction, and other systemic consequences. We also discuss implications for laboratory evaluation and clinical care, including the role of lifestyle modifications. Chronic energy imbalance produces adipocyte hypertrophy and hyperplasia, endoplasmic reticulum stress, and mitochondrial dysfunction. These processes lead to increased intracellular and systemic release of adipokines, free fatty acids, and inflammatory mediators that cause adipocyte dysfunction and induce adverse effects in the liver, pancreatic beta-cells, and skeletal muscle as well as the heart and vascular beds. Several specialized laboratory tests can quantify these processes and predict clinical risk, but translation to the clinical setting is premature. Current and future pharmacologic interventions may target these pathways; modest changes in diet, physical activity, weight, and smoking are likely to have the greatest impact. Adipocyte endoplasmic reticulum and mitochondrial stress, and associated changes in circulating adipokines, free fatty acids, and inflammatory mediators, are central to adverse health effects of adiposity. Future investigation should focus on these pathways and on reversing the adverse lifestyle behaviors that are the fundamental causes of adiposity.

Effect of Diabetes Mellitus on Adipocyte-Derived Stem Cells in Rat.

PubMed

Jumabay, Medet; Moon, Jeremiah H; Yeerna, Huwate; Boström, Kristina I

2015-11-01

Diabetes mellitus affects the adipose tissue and mesenchymal stem cells derived from the adipose stroma and other tissues. Previous reports suggest that bone morphogenetic protein 4 (BMP4) is involved in diabetic complications, at the same time playing an important role in the maintenance of stem cells. In this study, we used rats transgenic for human islet amyloid polypeptide (HIP rats), a model of type 2 diabetes, to study the effect of diabetes on adipocyte-derived stem cells, referred to as dedifferentiated fat (DFAT) cells. Our results show that BMP4 expression in inguinal adipose tissue is significantly increased in HIP rats compared to controls, whereas matrix Gla protein (MGP), an inhibitor of BMP4 is decreased as determined by quantitative PCR, and immunofluorescence. In addition, adipose vascularity and expression of multiple endothelial cell markers was increased in the diabetic tissue, visualized by immunofluorescence for endothelial markers. The endothelial markers co-localized with the enhanced BMP4 expression, suggesting that vascular cells play a role BMP4 induction. The DFAT cells are multipotent stem cells derived from white mature adipocytes that undergo endothelial and adipogenic differentiation. DFAT cells prepared from the inguinal adipose tissue in HIP rats exhibited enhanced proliferative capacity compared to wild type. In addition, their ability to undergo both endothelial cell and adipogenic lineage differentiation was enhanced, as well as their response to BMP4, as assessed by lineage marker expression. We conclude that the DFAT cells are affected by diabetic changes and may contribute to the adipose dysfunction in diabetes. © 2015 Wiley Periodicals, Inc.

The effect of insulin, TNFα and DHA on the proliferation, differentiation and lipolysis of preadipocytes isolated from large yellow croaker (Pseudosciaena Crocea R.).

PubMed

Wang, Xinxia; Huang, Ming; Wang, Yizhen

2012-01-01

Fish final product can be affected by excessive lipid accumulation. Therefore, it is important to develop strategies to control obesity in cultivated fish to strengthen the sustainability of the aquaculture industry. As in mammals, the development of adiposity in fish depends on hormonal, cytokine and dietary factors. In this study, we investigated the proliferation and differentiation of preadipocytes isolated from the large yellow croaker and examined the effects of critical factors such as insulin, TNFα and DHA on the proliferation, differentiation and lipolysis of adipocytes. Preadipocytes were isolated by collagenase digestion, after which their proliferation was evaluated. The differentiation process was optimized by assaying glycerol-3-phosphate dehydrogenase (GPDH) activity. Oil red O staining and electron microscopy were performed to visualize the accumulated triacylglycerol. Gene transcript levels were measured using SYBR green quantitative real-time PCR. Insulin promoted preadipocytes proliferation, stimulated cell differentiation and decreased lipolysis of mature adipocytes. TNFα and DHA inhibited cell proliferation and differentiation. While TNFα stimulated mature adipocyte lipolysis, DHA showed no lipolytic effect on adipocytes. The expressions of adipose triglyceride lipase (ATGL), fatty acid synthase (FAS), lipoprotein lipase (LPL) and peroxisome proliferator-activated receptor α, γ (PPARα, PPARγ) were quantified during preadipocytes differentiation and adipocytes lipolysis to partly explain the regulation mechanisms. In summary, the results of this study indicated that although preadipocytes proliferation and the differentiation process in large yellow croaker are similar to these processes in mammals, the effects of critical factors such as insulin, TNFα and DHA on fish adipocytes development are not exactly the same. Our findings fill in the gaps in the basic data regarding the effects of critical factors on adiposity development in fish

A biomimetic hydrogel functionalized with adipose ECM components as a microenvironment for the 3D culture of human and murine adipocytes.

PubMed

Louis, Fiona; Pannetier, Pauline; Souguir, Zied; Le Cerf, Didier; Valet, Philippe; Vannier, Jean-Pierre; Vidal, Guillaume; Demange, Elise

2017-08-01

The lack of relevant in vitro models for adipose tissue makes necessary the development of a more physiological environment providing spatial and chemical cues for the effective maturation of adipocytes. We developed a biofunctionalized hydrogel with components of adipose extracellular matrix: collagen I, collagen VI, and the cell binding domain of fibronectin and we compared it to usual 2D cultures on plastic plates. This scaffold allowed 3D culture of mature adipocytes from the preadipocytes cell lines 3T3-L1 and 3T3-F442A, as well as primary Human White Preadipocytes (HWP), acquiring in vivo-like organization, with spheroid shaped adipocytes forming multicellular aggregates. The size of these aggregates increased with time up to 120 μm in diameter after 4 weeks of maturation, with good viability. Significantly higher lipogenic activity (up to 20-fold at day 28 for HWP cultures) and differentiation rates were also observed compared to 2D. Gene expression analyses highlighted earlier differentiation and complete maturation of 3D HWP compared to 2D, reinforced by the expression of Perilipin protein after 21 days of nutrition. This increase in adipocytes phenotypic and genotypic markers made this scaffold-driven culture as a robust adipose 3D model. Retinoic acid inhibition of lipogenesis in HWP or isoprenalin and caffeine induction of lipolysis performed on mouse 3T3-F442A cells, showed higher doses of molecules than typically used in 2D, underlying the physiologic relevance of this 3D culture system. Biotechnol. Bioeng. 2017;114: 1813-1824. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Prenatal Exposure to the Environmental Obesogen Tributyltin Predisposes Multipotent Stem Cells to Become Adipocytes

PubMed Central

Kirchner, Séverine; Kieu, Tiffany; Chow, Connie; Casey, Stephanie; Blumberg, Bruce

2010-01-01

The environmental obesogen hypothesis proposes that pre- and postnatal exposure to environmental chemicals contributes to adipogenesis and the development of obesity. Tributyltin (TBT) is an agonist of both retinoid X receptor (RXR) and peroxisome proliferator-activated receptor γ (PPARγ). Activation of these receptors can elevate adipose mass in adult mice exposed to the chemical in utero. Here we show that TBT sensitizes human and mouse multipotent stromal stem cells derived from white adipose tissue [adipose-derived stromal stem cells (ADSCs)] to undergo adipogenesis. In vitro exposure to TBT, or the PPARγ activator rosiglitazone increases adipogenesis, cellular lipid content, and expression of adipogenic genes. The adipogenic effects of TBT and rosiglitazone were blocked by the addition of PPARγ antagonists, suggesting that activation of PPARγ mediates the effect of both compounds on adipogenesis. ADSCs from mice exposed to TBT in utero showed increased adipogenic capacity and reduced osteogenic capacity with enhanced lipid accumulation in response to adipogenic induction. ADSCs retrieved from animals exposed to TBT in utero showed increased expression of PPARγ target genes such as the early adipogenic differentiation gene marker fatty acid-binding protein 4 and hypomethylation of the promoter/enhancer region of the fatty acid-binding protein 4 locus. Hence, TBT alters the stem cell compartment by sensitizing multipotent stromal stem cells to differentiate into adipocytes, an effect that could likely increase adipose mass over time. PMID:20160124

Prenatal exposure to the environmental obesogen tributyltin predisposes multipotent stem cells to become adipocytes.

PubMed

Kirchner, Séverine; Kieu, Tiffany; Chow, Connie; Casey, Stephanie; Blumberg, Bruce

2010-03-01

The environmental obesogen hypothesis proposes that pre- and postnatal exposure to environmental chemicals contributes to adipogenesis and the development of obesity. Tributyltin (TBT) is an agonist of both retinoid X receptor (RXR) and peroxisome proliferator-activated receptor gamma (PPARgamma). Activation of these receptors can elevate adipose mass in adult mice exposed to the chemical in utero. Here we show that TBT sensitizes human and mouse multipotent stromal stem cells derived from white adipose tissue [adipose-derived stromal stem cells (ADSCs)] to undergo adipogenesis. In vitro exposure to TBT, or the PPARgamma activator rosiglitazone increases adipogenesis, cellular lipid content, and expression of adipogenic genes. The adipogenic effects of TBT and rosiglitazone were blocked by the addition of PPARgamma antagonists, suggesting that activation of PPARgamma mediates the effect of both compounds on adipogenesis. ADSCs from mice exposed to TBT in utero showed increased adipogenic capacity and reduced osteogenic capacity with enhanced lipid accumulation in response to adipogenic induction. ADSCs retrieved from animals exposed to TBT in utero showed increased expression of PPARgamma target genes such as the early adipogenic differentiation gene marker fatty acid-binding protein 4 and hypomethylation of the promoter/enhancer region of the fatty acid-binding protein 4 locus. Hence, TBT alters the stem cell compartment by sensitizing multipotent stromal stem cells to differentiate into adipocytes, an effect that could likely increase adipose mass over time.

Cannabidiol promotes browning in 3T3-L1 adipocytes.

PubMed

Parray, Hilal Ahmad; Yun, Jong Won

2016-05-01

Recruitment of the brown-like phenotype in white adipocytes (browning) and activation of existing brown adipocytes are currently being investigated as a means to combat obesity. Thus, a wide variety of dietary agents that contribute to browning of white adipocytes have been identified. The present study was designed to investigate the effects of cannabidiol (CBD), a major nonpsychotropic phytocannabinoid of Cannabis sativa, on induction of browning in 3T3-L1 adipocytes. CBD enhanced expression of a core set of brown fat-specific marker genes (Ucp1, Cited1, Tmem26, Prdm16, Cidea, Tbx1, Fgf21, and Pgc-1α) and proteins (UCP1, PRDM16, and PGC-1α). Increased expression of UCP1 and other brown fat-specific markers contributed to the browning of 3T3-L1 adipocytes possibly via activation of PPARγ and PI3K. In addition, CBD increased protein expression levels of CPT1, ACSL, SIRT1, and PLIN while down-regulating JNK2, SREBP1, and LPL. These data suggest possible roles for CBD in browning of white adipocytes, augmentation of lipolysis, thermogenesis, and reduction of lipogenesis. In conclusion, the current data suggest that CBD plays dual modulatory roles in the form of inducing the brown-like phenotype as well as promoting lipid metabolism. Thus, CBD may be explored as a potentially promising therapeutic agent for the prevention of obesity.

Enhancement of Adipocyte Browning by Angiotensin II Type 1 Receptor Blockade.

PubMed

Tsukuda, Kana; Mogi, Masaki; Iwanami, Jun; Kanno, Harumi; Nakaoka, Hirotomo; Wang, Xiao-Li; Bai, Hui-Yu; Shan, Bao-Shuai; Kukida, Masayoshi; Higaki, Akinori; Yamauchi, Toshifumi; Min, Li-Juan; Horiuchi, Masatsugu

2016-01-01

Browning of white adipose tissue (WAT) has been highlighted as a new possible therapeutic target for obesity, diabetes and lipid metabolic disorders, because WAT browning could increase energy expenditure and reduce adiposity. The new clusters of adipocytes that emerge with WAT browning have been named 'beige' or 'brite' adipocytes. Recent reports have indicated that the renin-angiotensin system (RAS) plays a role in various aspects of adipose tissue physiology and dysfunction. The biological effects of angiotensin II, a major component of RAS, are mediated by two receptor subtypes, angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R). However, the functional roles of angiotensin II receptor subtypes in WAT browning have not been defined. Therefore, we examined whether deletion of angiotensin II receptor subtypes (AT1aR and AT2R) may affect white-to-beige fat conversion in vivo. AT1a receptor knockout (AT1aKO) mice exhibited increased appearance of multilocular lipid droplets and upregulation of thermogenic gene expression in inguinal white adipose tissue (iWAT) compared to wild-type (WT) mice. AT2 receptor-deleted mice did not show miniaturization of lipid droplets or alteration of thermogenic gene expression levels in iWAT. An in vitro experiment using adipose tissue-derived stem cells showed that deletion of the AT1a receptor resulted in suppression of adipocyte differentiation, with reduction in expression of thermogenic genes. These results indicate that deletion of the AT1a receptor might have some effects on the process of browning of WAT and that blockade of the AT1 receptor could be a therapeutic target for the treatment of metabolic disorders.

A mechanically activated TRPC1-like current in white adipocytes.

PubMed

El Hachmane, Mickaël F; Olofsson, Charlotta S

2018-04-15

Ca 2+ impacts a large array of cellular processes in every known cell type. In the white adipocyte, Ca 2+ is involved in regulation of metabolic processes such as lipolysis, glucose uptake and hormone secretion. Although the importance of Ca 2+ in control of white adipocyte function is clear, knowledge is still lacking regarding the control of dynamic Ca 2+ alterations within adipocytes and mechanisms inducing intracellular Ca 2+ changes remain elusive. Own work has recently demonstrated the existence of store-operated Ca 2+ entry (SOCE) in lipid filled adipocytes. We defined stromal interaction molecule 1 (STIM1) and the calcium release-activated calcium channel protein 1 (ORAI1) as the key players involved in this process and we showed that the transient receptor potential (TRP) channel TRPC1 contributed to SOCE. Here we have aimed to further characterised SOCE in the white adipocyte by use of single cell whole-cell patch clamp recordings. The electrophysiological measurements show the existence of a seemingly constitutively active current that is inhibited by known store-operated Ca 2+ channel (SOCC) blockers. We demonstrate that the mechanical force applied to the plasma membrane upon patching leads to an elevation of the cytoplasmic Ca 2+ concentration and that this elevation can be reversed by SOCC antagonists. We conclude that a mechanically activated current with properties similar to TRPC1 is present in white adipocytes. Activation of TRPC1 by membrane tension/stretch may be specifically important for the function of this cell type, since adipocytes can rapidly increase or decrease in size. Copyright © 2018 Elsevier Inc. All rights reserved.

Cytoprotective role of the fatty acid binding protein 4 against oxidative and endoplasmic reticulum stress in 3T3-L1 adipocytes

PubMed Central

Kajimoto, Kazuaki; Minami, Yoshitaka; Harashima, Hideyoshi

2014-01-01

The fatty acid binding protein 4 (FABP4), one of the most abundant proteins in adipocytes, has been reported to have a proinflammatory function in macrophages. However, the physiological role of FABP4, which is constitutively expressed in adipocytes, has not been fully elucidated. Previously, we demonstrated that FABP4 was involved in the regulation of interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) production in 3T3-L1 adipocytes. In this study, we examined the effects of FABP4 silencing on the oxidative and endoplasmic reticulum (ER) stress in 3T3-L1 adipocytes. We found that the cellular reactive oxygen species (ROS) and 8-nitro-cyclic GMP levels were significantly elevated in the differentiated 3T3-L1 adipocytes transfected with a small interfering RNA (siRNA) against Fabp4, although the intracellular levels or enzyme activities of antioxidants including reduced glutathione (GSH), superoxide dismutase (SOD) and glutathione S-transferase A4 (GSTA4) were not altered. An in vitro evaluation using the recombinant protein revealed that FABP4 itself functions as a scavenger protein against hydrogen peroxide (H2O2). FABP4-knockdown resulted in a significant lowering of cell viability of 3T3-L1 adipocytes against H2O2 treatment. Moreover, four kinds of markers related to the ER stress response including the endoplasmic reticulum to nucleus signaling 1 (Ern1), the signal sequence receptor α (Ssr1), the ORM1-like 3 (Ormdl3), and the spliced X-box binding protein 1 (Xbp1s), were all elevated as the result of the knockdown of FABP4. Consequently, FABP4 might have a new role as an antioxidant protein against H2O2 and contribute to cytoprotection against oxidative and ER stress in adipocytes. PMID:25161868

The role of Rpgrip1l, a component of the primary cilium, in adipocyte development and function.

PubMed

Carli, Jayne F Martin; LeDuc, Charles A; Zhang, Yiying; Stratigopoulos, George; Leibel, Rudolph L

2018-02-21

Genetic variants within the FTO (α-ketoglutarate-dependent dioxygenase) gene have been strongly associated with a modest increase in adiposity as a result of increased food intake. These risk alleles are associated with decreased expression of both FTO and neighboring RPGRIP1L (retinitis pigmentosa GTPase regulator-interacting protein 1 like). RPGRIP1L encodes a protein that is critical to the function of the primary cilium, which conveys extracellular information to the cell. Rpgrip1l +/- mice exhibit increased adiposity, in part, as a result of hyperphagia. Here, we describe the effects of Rpgrip1l in adipocytes that may contribute to the adiposity phenotype observed in these animals and possibly in humans who segregate for FTO risk alleles. Loss of Rpgrip1l in 3T3-L1 preadipocytes increased the number of cells that are capable of differentiating into mature adipocytes. Knockout of Rpgrip1l in mature adipocytes using Adipoq-Cre did not increase adiposity in mice that were fed chow or a high-fat diet. We also did not observe any effects of Rpgrip1l knockdown in mature 3T3-L1 adipocytes. Thus, to the extent that Rpgrip1l affects cell-autonomous adipose tissue function, it may do so as a result of the effects conveyed in preadipocytes in which the primary cilium is functionally important. We propose that decreased RPGRIP1L expression in preadipocytes in humans who segregate for FTO obesity risk alleles may increase the storage capacity of adipose tissue.-Martin Carli, J. F., LeDuc, C. A., Zhang, Y., Stratigopoulos, G., Leibel, R. L. The role of Rpgrip1l, a component of the primary cilium, in adipocyte development and function.

Prostaglandin E2 signals white-to-brown adipogenic differentiation

PubMed Central

García-Alonso, Verónica; Clària, Joan

2014-01-01

The formation of new adipocytes from precursor cells is a crucial aspect of normal adipose tissue function. During the adipogenic process, adipocytes differentiated from mesenchymal stem cells give rise to two main types of fat: white adipose tissue (WAT) characterized by the presence of adipocytes containing large unilocular lipid droplets, and brown adipose tissue (BAT) composed by multilocular brown adipocytes packed with mitochondria. WAT is not only important for energy storage but also as an endocrine organ regulating whole body homeostasis by secreting adipokines and other mediators, which directly impact metabolic functions in obesity. By contrast, BAT is specialized in dissipating energy in form of heat and has salutary effects in combating obesity and associated disorders. Unfortunately, WAT is the predominant fat type, whereas BAT is scarce and located in discrete pockets in adult humans. Luckily, another type of brown adipocytes, called beige or brite (brown-in-white) adipocytes, with similar functions to those of “classical” brown adipocytes has recently been identified in WAT. In this review, a close look is given into the role of bioactive lipid mediators in the regulation of adipogenesis, with a special emphasis on the role of the microsomal prostaglandin E (PGE) synthase-1, a terminal enzyme in PGE2 biosynthesis, as a key regulator of white-to-brown adipogenesis in WAT. PMID:26317053

Invited review: Pre- and postnatal adipose tissue development in farm animals: from stem cells to adipocyte physiology.

PubMed

Louveau, I; Perruchot, M-H; Bonnet, M; Gondret, F

2016-11-01

Both white and brown adipose tissues are recognized to be differently involved in energy metabolism and are also able to secrete a variety of factors called adipokines that are involved in a wide range of physiological and metabolic functions. Brown adipose tissue is predominant around birth, except in pigs. Irrespective of species, white adipose tissue has a large capacity to expand postnatally and is able to adapt to a variety of factors. The aim of this review is to update the cellular and molecular mechanisms associated with pre- and postnatal adipose tissue development with a special focus on pigs and ruminants. In contrast to other tissues, the embryonic origin of adipose cells remains the subject of debate. Adipose cells arise from the recruitment of specific multipotent stem cells/progenitors named adipose tissue-derived stromal cells. Recent studies have highlighted the existence of a variety of those cells being able to differentiate into white, brown or brown-like/beige adipocytes. After commitment to the adipocyte lineage, progenitors undergo large changes in the expression of many genes involved in cell cycle arrest, lipid accumulation and secretory functions. Early nutrition can affect these processes during fetal and perinatal periods and can also influence or pre-determinate later growth of adipose tissue. How these changes may be related to adipose tissue functional maturity around birth and can influence newborn survival is discussed. Altogether, a better knowledge of fetal and postnatal adipose tissue development is important for various aspects of animal production, including neonatal survival, postnatal growth efficiency and health.

IL-6-Type Cytokine Signaling in Adipocytes Induces Intestinal GLP-1 Secretion.

PubMed

Wueest, Stephan; Laesser, Céline I; Böni-Schnetzler, Marianne; Item, Flurin; Lucchini, Fabrizio C; Borsigova, Marcela; Müller, Werner; Donath, Marc Y; Konrad, Daniel

2018-01-01

We recently showed that interleukin (IL)-6-type cytokine signaling in adipocytes induces free fatty acid release from visceral adipocytes, thereby promoting obesity-induced hepatic insulin resistance and steatosis. In addition, IL-6-type cytokines may increase the release of leptin from adipocytes and by those means induce glucagon-like peptide 1 (GLP-1) secretion. We thus hypothesized that IL-6-type cytokine signaling in adipocytes may regulate insulin secretion. To this end, mice with adipocyte-specific knockout of gp130, the signal transducer protein of IL-6, were fed a high-fat diet for 12 weeks. Compared with control littermates, knockout mice showed impaired glucose tolerance and circulating leptin, GLP-1, and insulin levels were reduced. In line, leptin release from isolated adipocytes was reduced, and intestinal proprotein convertase subtilisin/kexin type 1 ( Pcsk1 ) expression, the gene encoding PC1/3, which controls GLP-1 production, was decreased in knockout mice. Importantly, treatment with the GLP-1 receptor antagonist exendin 9-39 abolished the observed difference in glucose tolerance between control and knockout mice. Ex vivo, supernatant collected from isolated adipocytes of gp130 knockout mice blunted Pcsk1 expression and GLP-1 release from GLUTag cells. In contrast, glucose- and GLP-1-stimulated insulin secretion was not affected in islets of knockout mice. In conclusion, adipocyte-specific IL-6 signaling induces intestinal GLP-1 release to enhance insulin secretion, thereby counteracting insulin resistance in obesity. © 2017 by the American Diabetes Association.

Microarray profiling of gene expression in human adipocytes in response to anthocyanins.

PubMed

Tsuda, Takanori; Ueno, Yuki; Yoshikawa, Toshikazu; Kojo, Hitoshi; Osawa, Toshihiko

2006-04-14

Adipocyte dysfunction is strongly associated with the development of obesity and insulin resistance. It is accepted that the regulation of adipocytokine secretion or the adipocyte specific gene expression is one of the most important targets for the prevention of obesity and amelioration of insulin sensitivity. Recently, we demonstrated that anthocyanins, which are pigments widespread in the plant kingdom, have the potency of anti-obesity in mice and the enhancement adipocytokine secretion and its gene expression in adipocytes. In this study, we have shown the gene expression profile in human adipocytes treated with anthocyanins (cyanidin 3-glucoside; C3G or cyanidin; Cy). The human adipocytes were treated with 100 microM C3G, Cy or vehicle for 24 h. The total RNA from the adipocytes was isolated and carried out GeneChip microarray analysis. Based on the gene expression profile, we demonstrated the significant changes of adipocytokine expression (up-regulation of adiponectin and down-regulation of plasminogen activator inhibitor-1 and interleukin-6). Some of lipid metabolism related genes (uncoupling protein2, acylCoA oxidase1 and perilipin) also significantly induced in both common the C3G or Cy treatment groups. These studies have provided an overview of the gene expression profiles in human adipocytes treated with anthocyanins and demonstrated that anthocyanins can regulate adipocytokine gene expression to ameliorate adipocyte function related with obesity and diabetes that merit further investigation.

18{beta}-Glycyrrhetinic acid inhibits adipogenic differentiation and stimulates lipolysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moon, Myung-Hee; Jeong, Jae-Kyo; Lee, You-Jin

2012-04-20

Highlights: Black-Right-Pointing-Pointer 18{beta}-GA inhibits adipogenic differentiation in 3T3-L1 preadipocytes and stimulates lipolysis in differentiated adipocytes. Black-Right-Pointing-Pointer Anti-adipogenic effect of 18{beta}-GA is caused by down-regulation of PPAR{gamma} and inactivation of Akt signalling. Black-Right-Pointing-Pointer Lipolytic effect of 18{beta}-GA is mediated by up-regulation of HSL, ATGL and perilipin and activation of HSL. -- Abstract: 18{beta}-Glycyrrhetinic acid (18{beta}-GA) obtained from the herb liquorice has various pharmacological properties including anti-inflammatory and anti-bacterial activities. However, potential biological anti-obesity activities are unclear. In this study, novel biological activities of 18{beta}-GA in the adipogenesis of 3T3-L1 preadipocytes and in lipolysis of differentiated adipocytes were identified. Mouse 3T3-L1 cellsmore » were used as an in vitro model of adipogenesis and lipolysis, using a mixture of insulin/dexamethasone/3-isobutyl-1-methylxanthine (IBMX) to induce differentiation. The amount of lipid droplet accumulation was determined by an AdipoRed assay. The expression of several adipogenic transcription factors and enzymes was investigated using real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. 18{beta}-GA dose-dependently (1-40 {mu}M) significantly decreased lipid accumulation in maturing preadipocytes. In 3T3-L1 preadipocytes, 10 {mu}M of 18{beta}-GA down-regulated the transcriptional levels of the peroxisome proliferator-activated receptor {gamma}, CCAAT/enhancer-binding protein {alpha} and adiponectin, which are markers of adipogenic differentiation via Akt phosphorylation. Also, in differentiated adipocytes, 18{beta}-GA increased the level of glycerol release and up-regulated the mRNA of hormone-sensitive lipase, adipose TG lipase and perilipin, as well as the phosphorylation of hormone-sensitive lipase at Serine 563. The results indicate that 18

Low-dose radiation pretreatment improves survival of human ceiling culture-derived proliferative adipocytes (ccdPAs) under hypoxia via HIF-1 alpha and MMP-2 induction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adachi, Naoki; Kubota, Yoshitaka, E-mail: kubota-cbu@umin.ac.jp; Kosaka, Kentarou

2015-08-07

Poor survival is a major problem of adipocyte transplantation. We previously reported that VEGF and MMPs secreted from transplanted adipocytes are essential for angiogenesis and adipogenesis. Pretreatment with low-dose (5 Gy) radiation (LDR) increased VEGF, MMP-2, and HIF-1 alpha mRNA expression in human ceiling culture-derived proliferative adipocytes (hccdPAs). Gene expression after LDR differed between adipose-derived stem cells (hASCs) and hccdPAs. Pretreatment with LDR improved the survival of hccdPAs under hypoxia, which is inevitable in the early stages after transplantation. Upregulation of VEGF and MMP-2 after LDR in hccdPAs is mediated by HIF-1 alpha expression. Our results suggest that pretreatment with LDRmore » may improve adipocyte graft survival in a clinical setting through upregulation of VEGF and MMP-2 via HIF-1 alpha. - Highlights: • Ceiling culture-derived proliferative adipocytes (ccdPAs) react to radiation. • Low-dose radiation (LDR) pretreatment improves survival of ccdPAs under hypoxia. • Gene expression after LDR differs between ccdPAs and adipose-derived stem cells. • LDR-induced increase in MMP-2 and VEGF is dependent on HIF-1 alpha induction. • LDR pretreatment may improve the adipocyte graft survival rate in clinical settings.« less

White Tea extract induces lipolytic activity and inhibits adipogenesis in human subcutaneous (pre)-adipocytes

PubMed Central

Söhle, Jörn; Knott, Anja; Holtzmann, Ursula; Siegner, Ralf; Grönniger, Elke; Schepky, Andreas; Gallinat, Stefan; Wenck, Horst; Stäb, Franz; Winnefeld, Marc

2009-01-01

Background The dramatic increase in obesity-related diseases emphasizes the need to elucidate the cellular and molecular mechanisms underlying fat metabolism. To investigate how natural substances influence lipolysis and adipogenesis, we determined the effects of White Tea extract on cultured human subcutaneous preadipocytes and adipocytes. Methods For our in vitro studies we used a White Tea extract solution that contained polyphenols and methylxanthines. Utilizing cultured human preadipocytes we investigated White Tea extract solution-induced inhibition of triglyceride incorporation during adipogenesis and possible effects on cell viability. In vitro studies on human adipocytes were performed aiming to elucidate the efficacy of White Tea extract solution to stimulate lipolytic activity. To characterize White Tea extract solution-mediated effects on a molecular level, we analyzed gene expression of essential adipogenesis-related transcription factors by qRT-PCR and determined the expression of the transcription factor ADD1/SREBP-1c on the protein level utilizing immunofluorescence analysis. Results Our data show that incubation of preadipocytes with White Tea extract solution significantly decreased triglyceride incorporation during adipogenesis in a dose-dependent manner (n = 10) without affecting cell viability (n = 10). These effects were, at least in part, mediated by EGCG (n = 10, 50 μM). In addition, White Tea extract solution also stimulated lipolytic activity in adipocytes (n = 7). Differentiating preadipocytes cultivated in the presence of 0.5% White Tea extract solution showed a decrease in PPARγ, ADD1/SREBP-1c, C/EBPα and C/EBPδ mRNA levels. Moreover, the expression of the transcription factor ADD1/SREBP-1c was not only decreased on the mRNA but also on the protein level. Conclusion White Tea extract is a natural source that effectively inhibits adipogenesis and stimulates lipolysis-activity. Therefore, it can be utilized to modulate different

Kaempferol suppresses lipid accumulation by inhibiting early adipogenesis in 3T3-L1 cells and zebrafish.

PubMed

Lee, Yeon-Joo; Choi, Hyeon-Son; Seo, Min-Jung; Jeon, Hui-Jeon; Kim, Kui-Jin; Lee, Boo-Yong

2015-08-01

Kaempferol is a flavonoid present in Kaempferia galanga and Opuntia ficus indica var. saboten. Recent studies have suggested that it has anti-oxidant, anti-inflammatory, anti-cancer, and anti-obesity effects. In this study, we focused on the anti-adipogenic effects of kaempferol during adipocyte differentiation. The results showed that kaempferol inhibits lipid accumulation in adipocytes and zebrafish. Oil Red O and Nile Red staining showed that the number of intracellular lipid droplets decreased in adipocytes and zebrafish treated with kaempferol. LPAATθ (lysophosphatidic acid acyltransferase), lipin1, and DGAT1 (triglyceride synthetic enzymes) and FASN and SREBP-1C (fatty acid synthetic proteins) showed decreased expression levels in the presence of kaempferol. In addition, treatment of kaempferol showed an inhibitory activity on cell cycle progression. Kaempferol delayed cell cycle progression from the S to G2/M phase through the regulation of cyclins in a dose-dependent manner. Kaempferol blocked the phosphorylation of AKT (protein kinase B) and mammalian target of rapamycin (mTOR) signaling pathway during the early stages of adipogenesis. In addition, kaempferol down-regulated pro-early adipogenic factors such as CCAAT-enhancer binding proteins β (C/EBPβ), and Krüppel-like factors (KLFs) 4 and 5, while anti-early adipogenic factors, such as KLF2 and pref-1(preadipocyte factor-1), were upregulated. These kaempferol-mediated regulations of early adipogenic factors resulted in the attenuation of late adipogenic factors such as C/EBPα and peroxisome proliferator-activated receptor γ (PPARγ). These results were supported in zebrafish based on the decrease in lipid accumulation and expression of adipogenic factors. Our results indicated that kaempferol might have an anti-obesity effect by regulating lipid metabolism.

Decreased serum estrogen improves fat graft retention by enhancing early macrophage infiltration and inducing adipocyte hypertrophy.

PubMed

Mok, Hsiaopei; Feng, Jingwei; Hu, Wansheng; Wang, Jing; Cai, Junrong; Lu, Feng

2018-06-18

Fat grafting is a commonly used procedure; however, the mechanisms that regulate graft outcomes are not clear. Estrogen has been associated with vascularization, inflammation and fat metabolism, yet its role in fat grafting is unclear. Mice were implanted with 17β-estradiol pellets (high estrogen, HE), underwent ovariectomy (low estrogen level, OVX) or sham surgery (normal estrogen level, CON). 45 days later, inguinal fat of mice was autografted subcutaneously. At 1, 2, 4, and 12 weeks post-transplantation, grafts were dissected, weighed, and assessed for histology, angiogenesis and inflammation level. Serum estrogen level correlated to estrogen manipulation. 12 weeks after autografting, the retention rate was significantly higher in the OVX (79% ± 30%) than in the HE (16% ± 8%) and CON (35% ± 13%) groups. OVX-grafts had the least necrosis and most hypertrophic fat. OVX recruited the most pro-inflammatory macrophages and demonstrated a faster dead tissue removal process, however a higher fibrogenic tendency was found in this group. HE grafts had the most Sca1+ local stem cells and CD31  +  capillary content; however, with a low level of acute inflammation and insufficient adipokine PPAR-γ expression, their retention rate was impaired. Elevated serum estrogen increased stem cell density and early vascularization; however, by inhibiting the early inflammation, it resulted in delayed necrotic tissue removal and finally led to impaired adipose restoration. A low estrogen level induced favorable inflammation status and adipocyte hypertrophy to improve fat graft retention, but a continuing decreased estrogen level led to fat graft fibrosis. Copyright © 2018 Elsevier Inc. All rights reserved.

Relationship between epicardial adipose tissue adipocyte size and MCP-1 expression.

PubMed

Eiras, Sonia; Teijeira-Fernández, Elvis; Salgado-Somoza, Antonio; Couso, Elena; García-Caballero, Tomás; Sierra, Juan; Juanatey, José Ramón González

2010-08-01

Adipocyte size has been associated to increase in inflammatory cytokines expression that can be related to the cardiovascular risk of obesity. Epicardial adipose tissue (EAT) was discovered to play a key role in cardiovascular diseases by producing several inflammatory adipokines. We sought to study whether EAT and subcutaneous adipose tissue (SAT) mean adipocyte sizes are related to the expression of adipokines in patients with cardiovascular diseases. We collected EAT, SAT and blood samples from 22 patients aged 70.9 (s.d. 10.3) undergoing heart surgery. Monocyte chemoattractant protein (MCP)-1, interleukin (IL)-10 and tumor necrosis factor (TNF)-alpha were analyzed by real time RT-PCR, ELISA or immunohistochemistry. Hematoxylin-eosin staining was used for adipocyte area calculations. Adipocyte size is negatively correlated to MCP-1 expression (r=-0.475; p=0.034) in EAT and positively correlated in SAT (r=0.438; p=0.047). These trends persisted after stratification for sex and coronary artery disease (CAD), but only the relationship between EAT MCP-1 and adipocyte size reached statistical significance in the larger group of men with CAD. We have observed that SAT adipocyte size is correlated to BMI (r=0.601; p=0.003); whereas only a non-statistically significant trend was observed in EAT. IL-10 and TNF-alpha expression were not associated to adipocyte size in EAT nor SAT. Secondarily, we found that EAT IL-10 expression is higher in patients with CAD. These results suggest that adipocyte size is a negative determinant of MCP-1 expression in EAT and a positive determinant in SAT. These data might partly explain the different implications of EAT and SAT in cardiovascular diseases. Copyright 2010 Elsevier Ltd. All rights reserved.

Adverse effects of the classic antioxidant uric acid in adipocytes: NADPH oxidase-mediated oxidative/nitrosative stress.

PubMed

Sautin, Yuri Y; Nakagawa, Takahiko; Zharikov, Sergey; Johnson, Richard J

2007-08-01

Uric acid is considered a major antioxidant in human blood that may protect against aging and oxidative stress. Despite its proposed protective properties, elevated levels of uric acid are commonly associated with increased risk for cardiovascular disease and mortality. Furthermore, recent experimental studies suggest that uric acid may have a causal role in hypertension and metabolic syndrome. All these conditions are thought to be mediated by oxidative stress. In this study we demonstrate that differentiation of cultured mouse adipocytes is associated with increased production of reactive oxygen species (ROS) and uptake of uric acid. Soluble uric acid stimulated an increase in NADPH oxidase activity and ROS production in mature adipocytes but not in preadipocytes. The stimulation of NADPH oxidase-dependent ROS by uric acid resulted in activation of MAP kinases p38 and ERK1/2, a decrease in nitric oxide bioavailability, and an increase in protein nitrosylation and lipid oxidation. Collectively, our results suggest that hyperuricemia induces redox-dependent signaling and oxidative stress in adipocytes. Since oxidative stress in the adipose tissue has recently been recognized as a major cause of insulin resistance and cardiovascular disease, hyperuricemia-induced alterations in oxidative homeostasis in the adipose tissue might play an important role in these derangements.

ABCA1 in adipocytes regulates adipose tissue lipid content, glucose tolerance, and insulin sensitivity.

PubMed

de Haan, Willeke; Bhattacharjee, Alpana; Ruddle, Piers; Kang, Martin H; Hayden, Michael R

2014-03-01

Adipose tissue contains one of the largest reservoirs of cholesterol in the body. Adipocyte dysfunction in obesity is associated with intracellular cholesterol accumulation, and alterations in cholesterol homeostasis have been shown to alter glucose metabolism in cultured adipocytes. ABCA1 plays a major role in cholesterol efflux, suggesting a role for ABCA1 in maintaining cholesterol homeostasis in the adipocyte. However, the impact of adipocyte ABCA1 on adipose tissue function and glucose metabolism is unknown. Our aim was to determine the impact of adipocyte ABCA1 on adipocyte lipid metabolism, body weight, and glucose metabolism in vivo. To address this, we used mice lacking ABCA1 specifically in adipocytes (ABCA1(-ad/-ad)). When fed a high-fat, high-cholesterol diet, ABCA1(-ad/-ad) mice showed increased cholesterol and triglyceride stores in adipose tissue, developed enlarged fat pads, and had increased body weight. Associated with these phenotypic changes, we observed significant changes in the expression of genes involved in cholesterol and glucose homeostasis, including ldlr, abcg1, glut-4, adiponectin, and leptin. ABCA1(-ad/-ad) mice also demonstrated impaired glucose tolerance, lower insulin sensitivity, and decreased insulin secretion. We conclude that ABCA1 in adipocytes influences adipocyte lipid metabolism, body weight, and whole-body glucose homeostasis.

Arginine-vasopressin directly promotes a thermogenic and pro-inflammatory adipokine expression profile in brown adipocytes.

PubMed

Küchler, Sebastian; Perwitz, Nina; Schick, Rafael Reinhold; Klein, Johannes; Westphal, Sören

2010-09-24

Arginine-vasopressin (AVP) - via activation of the hypothalamic-pituitary-adrenal (HPA) axis - may play a role in the regulation of energy homeostasis and related cardiovascular complications. Brown adipose tissue (BAT) - via dissipation of energy in the form of heat - contributes to whole body energy balance. BAT expresses vasopressin receptors. We investigated direct effects of AVP on brown adipose endocrine and metabolic functions. UCP-1 protein expression in differentiated brown adipocytes was induced after acute exposure of adipocytes to AVP. This effect was time-dependent with a maximum increase after 8h. AVP also induced a time- and dose-dependent increase in p38 MAP kinase phosphorylation. Pharmacological inhibition of p38 MAP kinase with SB 202190 abolished the induction of UCP-1 protein expression. Furthermore, while acute AVP treatment enhanced mRNA expression of MCP-1 and IL-6, adiponectin mRNA expression was reduced. Yet, on the level of intracellular glucose uptake, there was no AVP-induced change of adipose insulin-induced glucose uptake. Finally, there was no difference in lipid accumulation between control and AVP-treated cells. Taken together, our data demonstrate direct effects of AVP on thermogenic, inflammatory, and glucoregulatory gene expression in brown adipocytes, thus expanding the hitherto known spectrum of this neuropeptides's biological effects and suggesting a direct adipotropic role as a stress-promoting factor. Copyright 2010 Elsevier B.V. All rights reserved.

Ectodermal Differentiation of Wharton's Jelly Mesenchymal Stem Cells for Tissue Engineering and Regenerative Medicine Applications.

PubMed

Jadalannagari, Sushma; Aljitawi, Omar S

2015-06-01

Mesenchymal stem cells (MSCs) from Wharton's jelly (WJ) of the human umbilical cord are perinatal stem cells that have self-renewal ability, extended proliferation potential, immunosuppressive properties, and are accordingly excellent candidates for tissue engineering. These MSCs are unique, easily accessible, and a noncontroversial cell source of regeneration in medicine. Wharton's jelly mesenchymal stem cells (WJMSCs) are multipotent and capable of multilineage differentiation into cells like adipocytes, bone, cartilage, and skeletal muscle upon exposure to appropriate conditions. The ectoderm is one of the three primary germ layers found in the very early embryo that differentiates into the epidermis, nervous system (spine, peripheral nerves, brain), and exocrine glands (mammary, sweat, salivary, and lacrimal glands). Accumulating evidence shows that MSCs obtained from WJ have an ectodermal differentiation potential. The current review examines this differentiation potential of WJMSC into the hair follicle, skin, neurons, and sweat glands along with discussing the potential utilization of such differentiation in regenerative medicine.

Generation of human adipose stem cells through dedifferentiation of mature adipocytes in ceiling cultures.

PubMed

Lessard, Julie; Côté, Julie Anne; Lapointe, Marc; Pelletier, Mélissa; Nadeau, Mélanie; Marceau, Simon; Biertho, Laurent; Tchernof, André

2015-03-07

Mature adipocytes have been shown to reverse their phenotype into fibroblast-like cells in vitro through a technique called ceiling culture. Mature adipocytes can also be isolated from fresh adipose tissue for depot-specific characterization of their function and metabolic properties. Here, we describe a well-established protocol to isolate mature adipocytes from adipose tissues using collagenase digestion, and subsequent steps to perform ceiling cultures. Briefly, adipose tissues are incubated in a Krebs-Ringer-Henseleit buffer containing collagenase to disrupt tissue matrix. Floating mature adipocytes are collected on the top surface of the buffer. Mature cells are plated in a T25-flask completely filled with media and incubated upside down for a week. An alternative 6-well plate culture approach allows the characterization of adipocytes undergoing dedifferentiation. Adipocyte morphology drastically changes over time of culture. Immunofluorescence can be easily performed on slides cultivated in 6-well plates as demonstrated by FABP4 immunofluorescence staining. FABP4 protein is present in mature adipocytes but down-regulated through dedifferentiation of fat cells. Mature adipocyte dedifferentiation may represent a new avenue for cell therapy and tissue engineering.

Sphingolipids Are Required for Efficient Triacylglycerol Loss in Conjugated Linoleic Acid Treated Adipocytes

PubMed Central

Wang, Wei; Fromm, Michael

2015-01-01

Conjugated linoleic acid (CLA) reduces adiposity in human and mouse adipocytes. This outcome is achieved through a variety of biological responses including increased energy expenditure and fatty acid oxidation, increased inflammation, repression of fatty acid biosynthesis, attenuated glucose transport, and apoptosis. In the current study, profiling of 261 metabolites was conducted to gain new insights into the biological pathways responding to CLA in 3T3-L1 adipocytes. Sphinganine and sphingosine levels were observed to be highly elevated in CLA treated adipocytes. Exogenous chemicals that increased endogenous ceramide levels decreased lipid levels in adipocytes, and activated AMP-activated protein kinase (AMPK) as well as NF-κB, both of which are typically activated in CLA treated adipocytes. Concurrent inhibition of ceramide de novo biosynthesis and recycling from existing sphingolipid pools attenuated the lipid lowering effect normally associated with responses to CLA, implicating ceramides as an important component of the lipid lowering response in CLA treated adipocytes. PMID:25906159

Involvement of IGF-1 and MEOX2 in PI3K/Akt1/2 and ERK1/2 pathways mediated proliferation and differentiation of perivascular adipocytes.

PubMed

Liu, Ping; Kong, Feng; Wang, Jue; Lu, Qinghua; Xu, Haijia; Qi, Tonggang; Meng, Juan

2015-02-01

Perivascular adipocyte (PVAC) proliferation and differentiation were closely involved in cardiovascular disease. We aimed to investigate whether phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) signaling pathways enhance PVAC functions activated by insulin-like growth factor 1(IGF-1) and suppressed by mesenchyme homeobox 2 (MEOX2). In this study, PVACs from primary culture were cultured and induced to differentiate. Cell viability assays demonstrated that IGF-1 promoted PVAC proliferation and differentiation. However MEOX2 counteracted these IGF-1-mediated actions. Flow Cytometry revealed that IGF-1 increased S phase cells and decreased apoptosis; however, MEOX2 decreased S phase cells, increased G0-G1 phase cells, and promoted apoptosis. During PVAC proliferation and differentiation, IGF-1 activated PI3K/Akt1/2 and ERK1/2 signaling pathways, upregulated the expression of these signaling proteins and FAS, and increased PVAC lipid content. In contrast, MEOX2 constrained the phosphorylation of ERK1/2 and Akt1/2 protein, down-regulated these signaling molecules and FAS, and decreased PVAC lipid content. Instead, MEOX2 knockdown enhanced the ERK1/2 and Akt1/2 phosphorylation, augmented the expression of these signaling molecules and FAS, and increased PVAC lipid content. Our findings suggested that PI3K/Akt1/2 and ERK1/2 activation mediated by IGF-1 is essential for PVAC proliferation and differentiation, and MEOX2 is a promising therapeutic gene to intervene in the signaling pathways and inhibit PVAC functions. Copyright © 2014 Elsevier Inc. All rights reserved.

Metformin induces oxidative stress in white adipocytes and raises uncoupling protein 2 levels.

PubMed

Anedda, Andrea; Rial, Eduardo; González-Barroso, M Mar

2008-10-01

Metformin is a drug widely used to treat type 2 diabetes. It enhances insulin sensitivity by improving glucose utilization in tissues like liver or muscle. Metformin inhibits respiration, and the decrease in cellular energy activates the AMP-activated protein kinase that in turn switches on catabolic pathways. Moreover, metformin increases lipolysis and beta-oxidation in white adipose tissue, thereby reducing the triglyceride stores. The uncoupling proteins (UCPs) are transporters that lower the efficiency of mitochondrial oxidative phosphorylation. UCP2 is thought to protect against oxidative stress although, alternatively, it could play an energy dissipation role. The aim of this work was to analyse the involvement of UCP2 on the effects of metformin in white adipocytes. We studied the effect of this drug in differentiating 3T3-L1 adipocytes and found that metformin causes oxidative stress since it increases the levels of reactive oxygen species (ROS) and lowers the aconitase activity. Variations in UCP2 protein levels parallel those of ROS. Metformin also increases lipolysis in these cells although only when the levels of ROS and UCP2 have decreased. Hence, UCP2 does not appear to be needed to facilitate fatty acid oxidation. Furthermore, treatment of C57BL/6 mice with metformin also augmented the levels of UCP2 in epididymal white adipose tissue. We conclude that metformin treatment leads to the overexpression of UCP2 in adipocytes to minimize the oxidative stress that is probably due to the inhibition of respiration caused by the drug.

A Novel Human Adipocyte-derived Basement Membrane for Tissue Engineering Applications

NASA Astrophysics Data System (ADS)

Damm, Aaron

Tissue engineering strategies have traditionally focused on the use of synthetic polymers as support scaffolds for cell growth. Recently, strategies have shifted towards a natural biologically derived scaffold, with the main focus on decellularized organs. Here, we report the development and engineering of a scaffold naturally secreted by human preadipocytes during differentiation. During this differentiation process, the preadipocytes remodel the extracellular matrix by releasing new extracellular proteins. Finally, we investigated the viability of the new basement membrane as a scaffold for tissue engineering using human pancreatic islets, and as a scaffold for soft tissue repair. After identifying the original scaffold material, we sought to improve the yield of material, treating the cell as a bioreactor, through various nutritional and cytokine stimuli. The results suggest that adipocytes can be used as bioreactors to produce a designer-specified engineered human extracellular matrix scaffold for specific tissue engineering applications.

The amine oxidase inhibitor phenelzine limits lipogenesis in adipocytes without inhibiting insulin action on glucose uptake.

PubMed

Carpéné, Christian; Grès, Sandra; Rascalou, Simon

2013-06-01

The antidepressant phenelzine is a monoamine oxidase inhibitor known to inhibit various other enzymes, among them semicarbazide-sensitive amine oxidase (currently named primary amine oxidase: SSAO/PrAO), absent from neurones but abundant in adipocytes. It has been reported that phenelzine inhibits adipocyte differentiation of cultured preadipocytes. To further explore the involved mechanisms, our aim was to study in vitro the acute effects of phenelzine on de novo lipogenesis in mature fat cells. Therefore, glucose uptake and incorporation into lipid were measured in mouse adipocytes in response to phenelzine, other hydrazine-based SSAO/PrAO-inhibitors, and reference agents. None of the inhibitors was able to impair the sevenfold activation of 2-deoxyglucose uptake induced by insulin. Phenelzine did not hamper the effect of lower doses of insulin. However, insulin-stimulated glucose incorporation into lipids was dose-dependently inhibited by phenelzine and pentamidine, but not by semicarbazide or BTT2052. In contrast, all these SSAO/PrAO inhibitors abolished the transport and lipogenesis stimulation induced by benzylamine. These data indicate that phenelzine does not inhibit glucose transport, the first step of lipogenesis, but inhibits at 100 μM the intracellular triacylglycerol assembly, consistently with its long-term anti-adipogenic effect and such rapid action was not found with all the hydrazine derivatives tested. Therefore, the alterations of body weight control consecutive to the use of this antidepressant drug might be not only related to central effects on food intake/energy expenditure, but could also depend on its direct action in adipocytes. Nonetheless, phenelzine antilipogenic action is not merely dependent on SSAO/PrAO inhibition.

An siRNA-based method for efficient silencing of gene expression in mature brown adipocytes.

PubMed

Isidor, Marie S; Winther, Sally; Basse, Astrid L; Petersen, M Christine H; Cannon, Barbara; Nedergaard, Jan; Hansen, Jacob B

2016-01-01

Brown adipose tissue is a promising therapeutic target for opposing obesity, glucose intolerance and insulin resistance. The ability to modulate gene expression in mature brown adipocytes is important to understand brown adipocyte function and delineate novel regulatory mechanisms of non-shivering thermogenesis. The aim of this study was to optimize a lipofection-based small interfering RNA (siRNA) transfection protocol for efficient silencing of gene expression in mature brown adipocytes. We determined that a critical parameter was to deliver the siRNA to mature adipocytes by reverse transfection, i.e. transfection of non-adherent cells. Using this protocol, we effectively knocked down both high- and low-abundance transcripts in a model of mature brown adipocytes (WT-1) as well as in primary mature mouse brown adipocytes. A functional consequence of the knockdown was confirmed by an attenuated increase in uncoupled respiration (thermogenesis) in response to β-adrenergic stimulation of mature WT-1 brown adipocytes transfected with uncoupling protein 1 siRNA. Efficient gene silencing was also obtained in various mouse and human white adipocyte models (3T3-L1, primary mouse white adipocytes, hMADS) with the ability to undergo "browning." In summary, we report an easy and versatile reverse siRNA transfection protocol to achieve specific silencing of gene expression in various models of mature brown and browning-competent white adipocytes, including primary cells.

Chilean Native Fruit Extracts Inhibit Inflammation Linked to the Pathogenic Interaction Between Adipocytes and Macrophages

PubMed Central

Reyes-Farias, Marjorie; Vasquez, Karla; Ovalle-Marin, Angelica; Fuentes, Francisco; Parra, Claudia; Quitral, Vilma; Jimenez, Paula

2015-01-01

Abstract Obesity is characterized by an increase in the infiltration of monocytes into the adipose tissue, causing an inflammatory condition associated with, for example, the development of insulin resistance. Thus, anti-inflammatory-based treatments could emerge as a novel and interesting approach. It has been reported that Chilean native fruits maqui (Aristotelia chilensis) and calafate (Berberis microphylla) present high contents of polyphenols, which are known for their antioxidant and anti-inflammatory properties. The aim of this study was to evaluate the ability of extracts of these fruits to block the pathogenic interaction between adipocytes and macrophages in vitro and to compare its effect with blueberry (Vaccinium corymbosum) extract treatment, which has been already described to possess several biomedical benefits. RAW264.7 macrophages were treated with 5 μg/mL lipopolysaccharides (LPS), with conditioned media (CM) from fully differentiated 3T3-L1 adipocytes, or in a coculture (CC) with 3T3-L1 adipocytes, in the presence or absence of 100 μM [total polyphenolic content] of each extract for 24 h. The gene expression and secretion profile of several inflammatory markers were evaluated. Nitric oxide secretion induced by LPS, CM, and CC was reduced by the presence of maqui (−12.2%, −45.6%, and −14.7%, respectively) and calafate (−27.6%, −43.9%, and −11.8%, respectively) extracts. Gene expression of inducible nitric oxide synthase and TNF-α was inhibited and of IL-10 was induced by maqui and calafate extract incubation. In conclusion, the extracts of these fruits present important inhibitory-like features over the inflammatory response of the interaction between adipocytes and macrophages, comprising a potential therapeutic tool against comorbidities associated with obesity development. PMID:25302660

Modest hypoxia significantly reduces triglyceride content and lipid droplet size in 3T3-L1 adipocytes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, Takeshi, E-mail: thashimo@fc.ritsumei.ac.jp; Yokokawa, Takumi; Endo, Yuriko

2013-10-11

Highlights: •Long-term hypoxia decreased the size of LDs and lipid storage in 3T3-L1 adipocytes. •Long-term hypoxia increased basal lipolysis in 3T3-L1 adipocytes. •Hypoxia decreased lipid-associated proteins in 3T3-L1 adipocytes. •Hypoxia decreased basal glucose uptake and lipogenic proteins in 3T3-L1 adipocytes. •Hypoxia-mediated lipogenesis may be an attractive therapeutic target against obesity. -- Abstract: Background: A previous study has demonstrated that endurance training under hypoxia results in a greater reduction in body fat mass compared to exercise under normoxia. However, the cellular and molecular mechanisms that underlie this hypoxia-mediated reduction in fat mass remain uncertain. Here, we examine the effects of modestmore » hypoxia on adipocyte function. Methods: Differentiated 3T3-L1 adipocytes were incubated at 5% O{sub 2} for 1 week (long-term hypoxia, HL) or one day (short-term hypoxia, HS) and compared with a normoxia control (NC). Results: HL, but not HS, resulted in a significant reduction in lipid droplet size and triglyceride content (by 50%) compared to NC (p < 0.01). As estimated by glycerol release, isoproterenol-induced lipolysis was significantly lowered by hypoxia, whereas the release of free fatty acids under the basal condition was prominently enhanced with HL compared to NC or HS (p < 0.01). Lipolysis-associated proteins, such as perilipin 1 and hormone-sensitive lipase, were unchanged, whereas adipose triglyceride lipase and its activator protein CGI-58 were decreased with HL in comparison to NC. Interestingly, such lipogenic proteins as fatty acid synthase, lipin-1, and peroxisome proliferator-activated receptor gamma were decreased. Furthermore, the uptake of glucose, the major precursor of 3-glycerol phosphate for triglyceride synthesis, was significantly reduced in HL compared to NC or HS (p < 0.01). Conclusion: We conclude that hypoxia has a direct impact on reducing the triglyceride content and lipid droplet

Characterisation of adipocyte-derived extracellular vesicle subtypes identifies distinct protein and lipid signatures for large and small extracellular vesicles

PubMed Central

Durcin, Maëva; Fleury, Audrey; Taillebois, Emiliane; Hilairet, Grégory; Krupova, Zuzana; Henry, Céline; Truchet, Sandrine; Trötzmüller, Martin; Köfeler, Harald; Mabilleau, Guillaume; Hue, Olivier; Andriantsitohaina, Ramaroson; Martin, Patrice; Le Lay, Soazig

2017-01-01

ABSTRACT Extracellular vesicles (EVs) are biological vectors that can modulate the metabolism of target cells by conveying signalling proteins and genomic material. The level of EVs in plasma is significantly increased in cardiometabolic diseases associated with obesity, suggesting their possible participation in the development of metabolic dysfunction. With regard to the poor definition of adipocyte-derived EVs, the purpose of this study was to characterise both qualitatively and quantitatively EVs subpopulations secreted by fat cells. Adipocyte-derived EVs were isolated by differential centrifugation of conditioned media collected from 3T3-L1 adipocytes cultured for 24 h in serum-free conditions. Based on morphological and biochemical properties, as well as quantification of secreted EVs, we distinguished two subpopulations of adipocyte-derived EVs, namely small extracellular vesicles (sEVs) and large extracellular vesicles (lEVs). Proteomic analyses revealed that lEVs and sEVs exhibit specific protein signatures, allowing us not only to define novel markers of each population, but also to predict their biological functions. Despite similar phospholipid patterns, the comparative lipidomic analysis performed on these EV subclasses revealed a specific cholesterol enrichment of the sEV population, whereas lEVs were characterised by high amounts of externalised phosphatidylserine. Enhanced secretion of lEVs and sEVs is achievable following exposure to different biological stimuli related to the chronic low-grade inflammation state associated with obesity. Finally, we demonstrate the ability of primary murine adipocytes to secrete sEVs and lEVs, which display physical and biological characteristics similar to those described for 3T3-L1. Our study provides additional information and elements to define EV subtypes based on the characterisation of adipocyte-derived EV populations. It also underscores the need to distinguish EV subpopulations, through a combination of

Mitophagy controls beige adipocyte maintenance through a Parkin-dependent and UCP1-independent mechanism.

PubMed

Lu, Xiaodan; Altshuler-Keylin, Svetlana; Wang, Qiang; Chen, Yong; Henrique Sponton, Carlos; Ikeda, Kenji; Maretich, Pema; Yoneshiro, Takeshi; Kajimura, Shingo

2018-04-24

Beige adipocytes are an inducible form of mitochondria-enriched thermogenic adipocytes that emerge in response to external stimuli, such as chronic cold exposure. We have previously shown that after the withdrawal of external stimuli, beige adipocytes directly acquire a white fat-like phenotype through autophagy-mediated mitochondrial degradation. We investigated the upstream pathway that mediates mitochondrial clearance and report that Parkin-mediated mitophagy plays a key role in the beige-to-white adipocyte transition. Mice genetically deficient in Park2 showed reduced mitochondrial degradation and retained thermogenic beige adipocytes even after the withdrawal of external stimuli. Norepinephrine signaling through the PKA pathway inhibited the recruitment of Parkin protein to mitochondria in beige adipocytes. However, mitochondrial proton uncoupling by uncoupling protein 1 (UCP1) was dispensable for Parkin recruitment and beige adipocyte maintenance. These results suggest a physiological mechanism by which external cues control mitochondrial homeostasis in thermogenic fat cells through mitophagy. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

The Novel Endocrine Disruptor Tolylfluanid Impairs Insulin Signaling in Primary Rodent and Human Adipocytes through a Reduction in Insulin Receptor Substrate-1 Levels