Keynote review: the adipocyte as a drug discovery target

Hypoglycemic and hypolipidemic effects of unsaponifiable matter from okra seed in diabetic rats

BACKGROUND/OBJECTIVES

Okra seed is a rich source of various nutritional and bioactive constituents, but its mechanism of action is still unclear. The aim of this study was to evaluated the effects on glucose uptake and serum lipid profiles of unsaponifiable matter (USM) from okra seed in adipocytes and diabetic animal models.

MATERIALS/METHODS

USM was prepared from okra seed powder by saponification. The contents of phytosterols and vitamin E in USM were measured. 3T3-L1 preadipocytes were cultured for 6 days with different concentrations of USM (0-200 μg/mL). The diabetic rats were administered with or without USM for 5 wk.

RESULTS

In the USM, the contents of phytosterols and vitamin E were 394.13 mg/g USM and 31.16 mg/g USM, respectively. USM showed no cytotoxicity and led to an approximately 1.4-fold increase in glucose uptake in 3T3-L1 adipocytes. The treatment of USM also increased the expressions of peroxisome proliferator-activated receptor-γ and glucose transporter-4 in a dose-dependent manner in adipocytes. The body weight change was not significantly different in all diabetic rats. However, blood glucose and the weights of liver and adipose tissues were significantly reduced compared to those in the control diabetic rats. Treatment with USM decreased the levels of triglycerides, total cholesterol, and low-density lipoprotein cholesterol compared to the control group. The USM group also showed significantly decreased atherogenic indices and cardiac risk factors.

CONCLUSION

These results suggest that USM from okra seed improves the hypoglycemic and hypolipidemic effects in diabetic rats, and provides valuable information for improving the functional properties of okra seed.

Anti-adipogenic and lipid-lowering activity of piperine and epigallocatechin gallate in 3T3-L1 adipocytes

The present study was aimed to evaluate the anti-adipogenic activity of piperine (PIP) and epigallocatechin gallate (EGCG) in 3T3-L1 cells. In cytotoxicity studies, PIP and EGCG showed IC50 values of 260 and 218 µM respectively and in combination (20 µM each) did not show cytotoxicity. Treatment with PIP and EGCG (20 µM each) significantly (p<.01) inhibited cell differentiation, lipid droplets deposition and enhanced glycerol release in 3T3-L1 cells. The secreted level of leptin was decreased but adiponectin level was increased in treated 3T3-L1 cells than untreated cells. In molecular expression studies, key adipogenic genes PPAR-γ, SREBP-1c, FAS, Fab-4, C/EBP-α and HMG-CoA reductase were markedly down-regulated but UCP-1 was up-regulated intreated 3T3-L1 cells and the same trend was observed in expression levels of selected proteins. In conclusion, our results demonstrated a combination of PIP and EGCG exhibited strong anti-adipogenic and lipid lowering effect than individual treatments due to synergism.

Comparing lipid remodeling of brown adipose tissue, white adipose tissue, and liver after one-week high fat diet intervention with quantitative Raman microscopy

Brown adipose tissue (BAT) consists of highly metabolically active adipocytes that catabolize nutrients to produce heat. Playing an active role in triacylglycerol (TAG) clearance, research has shown that dietary fatty acids can modulate the TAG chemistry deposition in BAT after weeks-long dietary intervention, similar to what has been shown in white adipose tissue (WAT). Our objective was to compare the influence of sustained, nonchronic dietary intervention (a 1-week interval) on WAT and interscapular BAT lipid metabolism and deposition in situ. We use quantitative, label-free chemical microscopy to show that 1 week of high fat diet (HFD) intervention results in dramatically larger lipid droplet (LD) growth in BAT (and liver) compared to LD growth in inguinal WAT (IWAT). Moreover, BAT showed lipid remodeling as increased unsaturated TAGs in LDs, resembling the dietary lipid composition, while WAT (and liver) did not show lipid remodeling on this time scale. Concurrently, expression of genes involved in lipid metabolism, particularly desaturases, was reduced in BAT and liver from HFD-fed mice after 1 week. Our data show that BAT lipid chemistry remodels exceptionally fast to dietary lipid intervention compared WAT, which further points towards a role in TAG clearance.

Astragalin, (3-O-glucoside of kaempferol), isolated from Moringa oleifera leaves modulates leptin, adiponectin secretion and inhibits adipogenesis in 3T3-L1 adipocytes

Inhibition of adipogenesis is crucial and is a key area of research to develop antiobesity drugs. In this study, 3-O-glucoside of kaempferol (astragalin) was isolated from Moringa oleifera leaves and evaluated for its lipolytic and antiadipogenic activity in 3T3-L1 adipocytes. Astragalin has substantially reduced the triglycerides content and lipid accumulation in 3T3-L1 adipocytes and enhanced the glycerol release in a dose dependent manner. The assay for secreted adipocytokines confirmed that, astragalin at a concentration of 20 µg/mL significantly (p < .01) increased the secretion of adiponectin, but decreased leptin secretion in 3T3-L1 adipocytes. In molecular studies, both the mRNA expression and corresponding protein expression of PPAR-γ, C/EBP-α, FAS, and leptin genes were downregulated while that of adiponectin was upregulated in astragalin treated groups. Taken together, astragalin of M. oleifera promotes lipolysis, suppresses adipogenesis in 3T3-L1 adipocytes, and may be considered as an effective candidate to treat obesity aliments.

Inhibitory effects of Rocaglamide-A on PPARγ-driven adipogenesis through regulation of mitotic clonal expansion involving the JAK2/STAT3 pathway

Inhibition of adipogenesis is an important strategy for obesity treatment. Rocaglamide-A (Roc-A) is a natural herbal medicine isolated from the genus Aglaia (family Meliaceae), which has a cyclopenta[b]benzofuran core structure. Roc-A exhibits various pharmacological effects against diverse human cancer cells. However, the exact role of Roc-A during adipogenesis in adipocytes has not been studied at all. In this study, we demonstrate that Roc-A is crucial for reducing adipogenesis via downregulating PPARγ transcriptional activity. Consistently, Western-blot and RT-PCR analyses clearly showed that Roc-A inhibits the expression of PPARγ target genes and lipogenic markers in a dose-dependent manner along with suppression of lipid accumulation, in both 3T3-L1 cells and mouse adipose-derived stem cells. Mechanistically, Roc-A significantly decreased JAK2/STAT3 phosphorylation in a dose-dependent manner in 3T3-L1 adipocytes. In particular, we confirmed that Roc-A effectively suppressed the expression of genes involved in cell-cycle regulation, such as cyclin A, B, D1, and E1, early during mitotic clonal expansion in 3T3-L1 adipocytes, and this effect was abolished by the JAK2/STAT3 activator FGF2. Taken together, our results demonstrated that Roc-A reduces adipogenesis by inhibiting PPARγ transactivation and JAK2/STAT3 phosphorylation and thus may serve as a therapeutic target in obesity.

Association of Cardiopulmonary Exercise Capacity and Adipokines in the General Population

Adipokines and cardiorespiratory fitness (CRF) are associated with the (patho)physiology of cardiometabolic diseases. Whether CRF and adipokines are related is unclear. We investigated associations of CRF with leptin, adiponectin, chemerin, resistin and vaspin. Data from the population-based Study of Health in Pomerania was used (n=1,479; median age 49 years; 51% women). Cardiopulmonary exercise testing was used to measure CRF. Circulating adipokine concentrations were measured by enzyme-linked immunosorbent assay. The association between CRF and adipokines was assessed using multivariable sex-specific quantile regression models. Higher maximum oxygen uptake was significantly associated with lower leptin (men:-0.11 ng/ml; 95%-confidence interval [CI]:-0.18 to-0.03 ng/ml; p<0.005; women:-0.17 ng/ml; 95%-CI:-0.33 to-0.02 ng/ml; p<0.05) and chemerin (men:-0.26 ng/ml; 95%-CI:-0.52 to-0.01 ng/ml; p<0.05; women:-0.41 ng/ml; 95%-CI:-0.82 to-0.01 ng/ml; p<0.05) as well as higher adiponectin concentrations (men: 0.06 µg/ml; 95%-CI: 0.02 to 0.11 µg/ml; p<0.05; women: 0.03 µg/ml; 95%-CI:-0.05 to 0.10 µg/ml; p=0.48). We found that CRF was inversely associated with leptin and chemerin in both sexes and positively associated with adiponectin only in men.

A 3D human adipose tissue model within a microfluidic device

An accurate in vitro model of human adipose tissue could assist in the study of adipocyte function and allow for better tools for screening new therapeutic compounds. Cell culture models on two-dimensional surfaces fall short of mimicking the three-dimensional in vivo adipose environment, while three-dimensional culture models are often unable to support long-term cell culture due, in part, to insufficient mass transport. Microfluidic systems have been explored for adipose tissue models. However, current systems have primarily focused on 2D cultured adipocytes. In this work, a 3D human adipose microtissue was engineered within a microfluidic system. Human adipose-derived stem cells (ADSCs) were used as the cell source for generating differentiated adipocytes. The ADSCs differentiated within the microfluidic system formed a dense lipid-loaded mass with the expression of adipose tissue genetic markers. Engineered adipose tissue showed a decreased adiponectin secretion and increased free fatty acid secretion with increasing shear stress. Adipogenesis markers were downregulated with increasing shear stress. Overall, this microfluidic system enables the on-chip differentiation and development of a functional 3D human adipose microtissue supported by the interstitial flow. This system could potentially serve as a platform for in vitro drug testing for adipose tissue-related diseases.

Potential Antidiabetic Fumiquinazoline Alkaloids from the Marine-Derived Fungus Scedosporium apiospermum F41-1

Fumiquinazoline alkaloids have attracted much attention from medicinal and natural product chemists due to their interesting structures and biological potential. In this study, three new and 12 known fumiquinazoline alkaloids were isolated and characterized from the marine fungus Scedosporium apiospermum F41-1. The structures of the new compounds and their absolute configurations were determined using NMR spectroscopy, ECD, and OR calculations. The compounds were evaluated for their antidiabetic potential by determining their triglyceride-promoting activity using 3T3-L1 adipocytes. One of the new compounds, scequinadoline J (14), as well as scequinadolines D (9) and E (10), was found to promote triglyceride accumulation in 3T3-L1 cells. Scequinadoline D (9) demonstrated the most potent activity, with an EC₅₀ value of 0.27 ± 0.03 μM. Quantitative polymerase chain reaction experiments suggested that scequinadoline D (9) acts through activation of the PPARγ pathway. It stimulated the mRNA expression of PPARγ, AMPKα, C/EBPα, LXRα, SCD-1, and FABP4. In addition, its triglyceride-promoting efficacy could be blocked by a double dose of the PPARγ antagonist GW9662. These results indicated that scequinadoline D (9) is a potent insulin sensitizer that targets adipocytes and may be useful for the treatment of type 2 diabetes mellitus after further investigation.

WAT-on-a-chip integrating human mature white adipocytes for mechanistic research and pharmaceutical applications

Obesity and its numerous adverse health consequences have taken on global, pandemic proportions. White adipose tissue (WAT) - a key contributor in many metabolic diseases - contributes about one fourth of a healthy human's body mass. Despite its significance, many WAT-related pathophysiogical mechanisms in humans are still not understood, largely due to the reliance on non-human animal models. In recent years, Organ-on-a-chip (OoC) platforms have developed into promising alternatives for animal models; these systems integrate engineered human tissues into physiological microenvironment supplied by a vasculature-like microfluidic perfusion. Here, we report the development of a novel OoC that integrates functional mature human white adipocytes. The WAT-on-a-chip is a multilayer device that features tissue chambers tailored specifically for the maintenance of 3D tissues based on human primary adipocytes, with supporting nourishment provided through perfused media channels. The platform's capability to maintain long-term viability and functionality of white adipocytes was confirmed by real-time monitoring of fatty acid uptake, by quantification of metabolite release into the effluent media as well as by an intact responsiveness to a therapeutic compound. The novel system provides a promising tool for wide-ranging applications in mechanistic research of WAT-related biology, in studying of pathophysiological mechanisms in obesity and diabetes, and in R&D of pharmaceutical industry.

Ginger Water Reduces Body Weight Gain and Improves Energy Expenditure in Rats

Obesity is a serious global problem that causes predisposition to numerous serious diseases. The current study aims to investigate the effect of ginger water on body weight and energy expenditure through modulation of mRNA expression of carbohydrate and lipid metabolism. A white colored liquid obtained during freeze-drying of fresh rhizomes of Zingiber officinal was collected and named ginger water. It was used to treat rats, then blood and tissue samples were collected from the liver and white adipose at the end of the experiment. The serum was prepared and used for biochemical assays, while tissue samples were used for RNA isolation and gene expression analysis via Reverse transcription polymerase chain reaction (RT-PCR). Results of High Performance Liquid Chromatography (HPLC) analysis of ginger water revealed the presence of chrysin and galangin at concentrations of 0.24 µg/mL and 0.53 µg/mL, respectively. Average body weight gain decreased significantly in groups that received ginger water. In addition, both total cholesterol and serum triacylglycerol were reduced in the groups that received ginger water. Furthermore, mRNA expression of Sterol regulatory element-binding protein 1 (SREBP-1c) in the liver and leptin in adipose tissues were downregulated, while those of adiponectin, hepatic carnitine palmitoyltransferase1 (CPT-1), acyl-coA oxidase (ACO), Glucose transporter 2 (GLUT-2), and pyruvate kinase (PK) were upregulated in ginger water-treated groups. These results clearly revealed the lowering body weight gain effect of ginger water, which most likely occurs at the transcriptional level of energy metabolizing proteins.

Adiponectin homolog osmotin, a potential anti-obesity compound, suppresses abdominal fat accumulation in C57BL/6 mice on high-fat diet and in 3T3-L1 adipocytes

OBJECTIVES

Obesity is characterized by excessive fat accumulation due to an imbalance between energy intake and expenditure. Osmotin, a plant derived natural protein, is a known homolog of adiponectin. To analyze the role of Osmotin in controlling energy metabolism by suppressing abdominal fat accumulation.

METHODS

We investigated the effects of osmotin in C57BL/6 mice on high-fat diet and in 3T3-L1 adipocytes by Biochemical tests, Immunofluorescence confocal Microscopy, RT-PCR, and Flow cytometry.

RESULTS

In this study, we investigated the anti-obesity effects of osmotin on adipocyte differentiation and regulation of the related factors lipolysis and glucose uptake in 3T3-L1 cells in vitro. Moreover, we analyzed the role of osmotin in prevention of insulin resistance, excess fat accumulation and metabolic syndrome in high-fat diet mouse model via AMPK and MAPK pathways in vivo. In addition, osmotin caused cell cycle arrest in G₀/G₁ phase by regulating expression of p21, p27 and CDK2 and improved glucose control, as concluded from glucose and insulin tolerance tests.

CONCLUSION

These results reveal the role of osmotin in AMPK downstream signaling. These results provide the first indication that osmotin exerts therapeutic effects on obesity, which could promote development of therapeutic aspects for obesity and related diseases.

Isoimperatorin enhances 3T3-L1 preadipocyte differentiation by regulating PPARγ and C/EBPα through the Akt signaling pathway

Lipodystrophic patients have an adipose tissue triglyceride storage defect that causes ectopic lipid accumulation, leading to severe insulin resistance. The present study investigated the potential role of isoimperatorin on 3T3-L1 adipocyte differentiation. mRNA and protein levels of differentiation- and lipid accumulation-associated genes, as well as the adipogenesis-related signaling pathway were analyzed in control and isoimperatorin-treated differentiated 3T3-L1 adipocytes using reverse transcription-quantitative PCR and western blot analysis. Results determined that isoimperatorin promoted 3T3-L1 fibroblast adipogenesis in a dose-dependent manner compared with standard differentiation inducers. Isoimperatorin significantly increased mRNA and protein expression of the crucial adipogenic transcription factors peroxisome proliferator activated receptor-γ (PPARγ) and CCAAT enhancer binding protein-α (C/EBPα). mRNA expression of the downstream adipogenesis-related genes sterol regulatory element-binding transcription factor 1c, adipocyte protein 2, fatty acid synthase, adiponectin and diacylglycerol O-acyltransferase 2 were also significantly increased following isoimperatorin treatment. The underlying mechanism likely involved activation of the Akt signaling pathway. Taken together, the present findings indicated that isoimperatorin may alter PPARγ and C/EBPα expression via the Akt signaling pathway, resulting in promotion of adipogenesis. The results highlighted the potential use of isoimperatorin as a therapeutic agent for preventing diabetes.

Reversal of high fat diet-induced obesity through modulating lipid metabolic enzymes and inflammatory markers expressions in rats

In this study, we evaluated the ameliorative potential of Cucurbita maxima seeds oil (CSO (100 mg/kg body weight)) supplementation to high fat diet (HFD)-induced obese rats for 30 days on the changes in body weight, markers of lipid metabolism such as LDL, HDL, triglycerides, total cholesterol, adiponectin, leptin, amylase, and lipase. We also investigated the effects of CSO on the changes of lipid metabolic enzymes such as fatty-acid synthase, acetyl CoA carboxylase, carnitine palmitoyl transferase-1, HMG CoA reductase, and inflammatory markers (TNF-α and IL-6). Administration of CSO revealed significant diminution in body weight gain, altered the activity, expressions of lipid marker enzymes and inflammatory markers. It demonstrated that CSO had considerably altered these parameters when evaluated with HFD control rats. In conclusion, this study suggested that CSO might ameliorate the HFD-induced obesity by altering the enzymes and mRNA expressions important to lipid metabolism.

Dietary supplement of Smilax china L. ethanol extract alleviates the lipid accumulation by activating AMPK pathways in high-fat diet fed mice

Background

Obesity has become a public health concern worldwide because it is linked to numerous metabolic disorders, such as hyperlipidemia, hypertension and cardiovascular disease. Therefore, there is an urgent need to develop new therapeutic strategies that are efficacious and have minimal side effects in obesity treatment. This study examined the effect of dietary supplement of Smilax china L. ethanol extract (SCLE) on high-fat diet (HFD) induced obesity.

Methods

Fifty ICR mice were fed a normal diet, high-fat diet (HFD) or HFD supplemented with 0.25, 0.5% or 1% SCLE for 8 weeks. Body weight, intraperitioneal adipose tissue (IPAT) weight, serum biochemical parameters, and liver lipids were measured. Activity, mRNA and protein expressions of lipid metabolism-related enzymes were analyzed.

Results

Over 0.5% SCLE had reduced cholesterol biosynthesis by the activation of AMP-activated protein kinase (AMPK), which subsequently suppressed the mRNA expression of both sterol regulatory element binding protein-2 and 3-hydroxy-3-methyl-glutaryl-CoA reductase. Thus, the plasma and liver cholesterol concentrations in the HFD-fed mice were decreased. AMPK activation caused by SCLE also significantly upregulated lipolysis by enhancing adipose triglyceride lipase and hormone-sensitive lipase activities. This accelerated triglyceride hydrolysis and fatty acid release. Finally, SCLE increased carnitine palmitoyltransferase 1 and acyl-CoA oxidase activities, which further promoted fatty acid β-oxidation.

Conclusion

SCLE could lead to a decrease in body weight gain and fat mass by inhibiting the lipid synthesis and promoting lipolysis and β-oxidation in HFD fed mice. The underlying mechanism is probably associated with regulating AMPK pathway.

Multiscale Imaging of Brown Adipose Tissue in Living Mice/Rats with Fluorescent Polymer Dots

Brown adipose tissue (BAT) has been identified as a promising target for the treatment of obesity, diabetes, and relevant metabolism disorders because of the adaptive thermogenesis ability of this tissue. Visualizing BAT may provide an essential tool for pathology study, drug screening, and efficacy evaluation. Owing to limitations of current nuclear and magnetic resonance imaging approaches for BAT detection, fluorescence imaging has advantages in large-scale preclinical research on small animals. Here, fast BAT imaging in mice is conducted based on polymer dots as fluorescent probes. As early as 5 min after the intravenous injection of polymer dots, extensive fluorescence is detected in the interscapular BAT and axillar BAT. In addition, axillar and inguinal white adipose tissues (WAT) are recognized. The real-time in vivo behavior of polymer dots in rodents is monitored using the probe-based confocal laser endomicroscopy imaging, and the preferred accumulation in BAT over WAT is confirmed by histological assays. Moreover, the whole study is conducted without a low temperature or pharmaceutical stimulation. The imaging efficacy is verified at the cellular, histological, and whole-body levels, and the present results indicate that fluorescent polymer dots may be a promising tool for the visualization of BAT in living subjects.

Oroxylum indicum (L.) Kurz extract inhibits adipogenesis and lipase activity in vitro

Background

Oroxylum indicum (L.) Kurz (O. indicum) is found in Thailand. It has been used for the treatment of obesity. This study aimed to investigate the effects of an O. indicum extract (OIE) on the adipogenic and biomolecular change in 3T3-L1 adipocytes.

Methods

Initial studies examined the chemical components of OIE. The cell line 3T3-L1 was used to establish potential toxic effects of OIE during the differentiation of pre-adipocytes to adipocytes. The inhibitory effect of OIE on lipid accumulation in 3T3-L1 cells was investigated. Moreover, the impact of OIE on pancreatic lipase activity was determined. In further experiments, Fourier Transform Infrared (FTIR) was used to monitor and discriminate biomolecular changes caused by the potential anti-adipogenic effect of OIE on 3T3-L1 cells.

Results

Chemical screening methods indicated that OIE was composed of flavonoids, alkaloids, steroids, glycosides, and tannins. The percentage viability of 3T3-L1 cells was not significantly decreased after exposure to either 200 or 150 μg/mL of OIE for 2 and 10 days, respectively compared to control cells. The OIE exhibited a dose-dependent reduction of lipid accumulation compared to the control (p < 0.05). The extract also demonstrated a dose-dependent inhibitory effect upon lipase activity compared to the control. The inhibitory effect of the OIE on lipid accumulation in 3T3-L1 cells was also confirmed using FTIR microspectroscopy. The signal intensity and the integrated areas relating to lipids, lipid esters, nucleic acids, glycogen and carbohydrates of the OIE-treated 3T3-L1 adipocytes were significantly lower than the non-treated 3T3-L1 adipocytes (p < 0.05). Principal component analysis (PCA) indicated four distinct clusters for the FTIR spectra of 3T3-L1 adipocytes based on biomolecular changes (lipids, proteins, nucleic acids, and carbohydrates). This observation was confirmed using Unsupervised hierarchical cluster analysis (UHCA).

Conclusions

These novel findings provide evidence that the OIE derived from the fruit pods of the plant is capable of inhibiting lipid and carbohydrate accumulation in adipocytes and also has the potential to inhibit an enzyme associated with fat absorption. The initial observations indicate that OIE may have important properties which in the future may be exploited for the management of the overweight or obese.

The role of adiponectin and adipolin as anti-inflammatory adipokines in the formation of macrophage foam cells and their association with cardiovascular diseases

Obesity is one of the major public health concerns that is closely associated with obesity-related disorders such as type 2 diabetes mellitus (T2DM), hypertension, and atherosclerosis. Atherosclerosis is a chronic disease characterized by excess cholesterol deposition in the arterial intima and the formation of foam cells. Adipocytokines or adipokines are secreted by the adipose tissue as endocrine glands; adiponectin and adipolin are among these adipokines that are associated with obese and insulin-resistant phenotypes. Adipolin and adiponectin are cytokines that exert substantial impact on obesity, progression of atherosclerosis, insulin resistance, and glucose metabolism. In this paper, we review the formation of macrophage foam cells, which are associated with atherosclerosis, and the macrophage mechanism, which includes uptake, esterification, and release. We also summarize current information on adipose tissue-derived hormone and energy homeostasis in obesity. Finally, the role of adipokines, e.g., adipoline and adiponectin, in regulating metabolic, cardiovascular diseases is discussed.

Anti obese potential of Cucurbita maxima seeds oil: effect on lipid profile and histoarchitecture in high fat diet induced obese rats

In this study, we made an attempt to evaluate the potential of Cucurbita maxima seeds oil (CSO) against high-fat diet (HFD)-induced obesity in rats. We investigated the effect of CSO (100 mg/kg body weight) supplementation over 30 days on the changes of HFD-induced obese rats in body weight, biochemical parameters and lipid profile as well as investigated the effects of CSO on the histopathological changes. Oral administration with CSO revealed significant diminution in body weight gain, glucose and insulin levels, which altered the activity of lipid profile and restored the pathological alterations. It demonstrated that CSO had considerably altered these parameters when evaluated with HFD control rats. In conclusion, this study established that CSO prevents the HFD-induced obesity by altering the markers important to lipid metabolism.

Anthocyanins from Purple Corn Ameliorated Tumor Necrosis Factor-α-Induced Inflammation and Insulin Resistance in 3T3-L1 Adipocytes via Activation of Insulin Signaling and Enhanced GLUT4 Translocation

SCOPE

The aim was to compare the effect of an anthocyanin-rich extract from purple corn pericarp (PCW) and pure anthocyanins on adipogenesis, inflammation, and insulin resistance in 3T3-L1 adipocytes on basal and inflammatory conditions.

METHODS AND RESULTS

Preadipocytes (3T3-L1) were treated during differentiation with or without PCW. Differentiated adipocytes were treated either individually or in combination with tumor necrosis factor α (TNF-α) and PCW, or pure C3G, Pr3G, P3G. PCW reduced preadipocyte differentiation (IC₅₀ = 0.4 mg/mL). PCW and pure anthocyanins including C3G reduced fatty acid synthase enzymatic activity. PCW reduced TNF-α-dependent inflammatory status increasing adiponectin (39%), and decreasing leptin (-79%). PCW and C3G increased glucose uptake and reduced reactive oxygen species generation in insulin resistant adipocytes. An increase in phosphorylation was observed in AKT, IKK, and MEK, and a decrease in IRS and mTOR activating the insulin receptor-associated pathway. PCW (7.5-fold) and C3G (6.3-fold) enhanced GLUT4 membrane translocation compared to insulin resistant adipocytes.

CONCLUSION

Anthocyanins from colored corn prevented adipocyte differentiation, lipid accumulation, and reduced PPAR-γ transcriptional activity on adipocytes in basal conditions. Ameliorated TNF-α-induced inflammation and insulin resistance in adipocytes via activation of insulin signaling and enhanced GLUT4 translocation suggesting a reduced hyperglycemia associated with the metabolic syndrome.

Flavonoids from Tetracera indica Merr. induce adipogenesis and exert glucose uptake activities in 3T3-L1 adipocyte cells

BACKGROUND

Tetracera indica Merr. (Family: Dilleniaceae), known to the Malay as 'Mempelas paya', is one of the medicinal plants used in the treatment of diabetes in Malaysia. However, no proper scientific study has been carried out to verify the traditional claim of T. indica as an antidiabetic agent. Hence, the aims of the present study were to determine the in vitro antidiabetic potential of the T. indica stems ethanol extract, subfractions and isolated compounds.

METHODS

The ethanol extract and its subfractions, and isolated compounds from T. indica stems were subjected to cytotoxicity test using MTT viability assay on 3T3-L1 pre-adipocytes. Then, the test groups were subjected to the in vitro antidiabetic investigation using 3T3-L1 pre-adipocytes and differentiated adipocytes to determine the insulin-like and insulin sensitizing activities. Rosiglitazone was used as a standard antidiabetic agent. All compounds were also subjected to fluorescence glucose (2-NBDG) uptake test on differentiated adipocytes. Test solutions were introduced to the cells in different safe concentrations as well as in different adipogenic cocktails, which were modified by the addition of compounds to be investigated and in the presence or absence of insulin. Isolation of bioactive compounds from the most effective subfraction (ethyl acetate) was performed through repeated silica gel and sephadex LH-20 column chromatographies and their structures were elucidated through 1H-and 13C-NMR spectroscopy.

RESULTS

Four monoflavonoids, namely, wogonin, norwogonin, quercetin and techtochrysin were isolated from the T. indica stems ethanol extract. Wogonin, norwogonin and techtochrysin induced significant (P < 0.05) adipogenesis like insulin and enhanced adipogenesis like rosiglitazone. Wogonin and norwogonin also exhibited significant (P < 0.05) glucose uptake activity.

CONCLUSION

The present study demonstrated that the flavonoids isolated from the T. indica stems possess antidiabetic potential revealing insulin-like and insulin-sensitizing effects which were significant among the compounds. This also rationalizes the traditional use of T. indica in the management of diabetes in Malaysia.

WAT-on-a-chip: a physiologically relevant microfluidic system incorporating white adipose tissue

Organ-on-a-chip systems possess a promising future as drug screening assays and as testbeds for disease modeling in the context of both single-organ systems and multi-organ-chips. Although it comprises approximately one fourth of the body weight of a healthy human, an organ frequently overlooked in this context is white adipose tissue (WAT). WAT-on-a-chip systems are required to create safety profiles of a large number of drugs due to their interactions with adipose tissue and other organs via paracrine signals, fatty acid release, and drug levels through sequestration. We report a WAT-on-a-chip system with a footprint of less than 1 mm2 consisting of a separate media channel and WAT chamber connected via small micropores. Analogous to the in vivo blood circulation, convective transport is thereby confined to the vasculature-like structures and the tissues protected from shear stresses. Numerical and analytical modeling revealed that the flow rates in the WAT chambers are less than 1/100 of the input flow rate. Using optimized injection parameters, we were able to inject pre-adipocytes, which subsequently formed adipose tissue featuring fully functional lipid metabolism. The physiologically relevant microfluidic environment of the WAT-chip supported long term culture of the functional adipose tissue for more than two weeks. Due to its physiological, highly controlled, and computationally predictable character, the system has the potential to be a powerful tool for the study of adipose tissue associated diseases such as obesity and type 2 diabetes.

Quantitative analysis of rat adipose tissue cell recovery, and non-fat cell volume, in primary cell cultures

BACKGROUND

White adipose tissue (WAT) is a complex, diffuse, multifunctional organ which contains adipocytes, and a large proportion of fat, but also other cell types, active in defense, regeneration and signalling functions. Studies with adipocytes often require their isolation from WAT by breaking up the matrix of collagen fibres; however, it is unclear to what extent adipocyte number in primary cultures correlates with their number in intact WAT, since recovery and viability are often unknown.

EXPERIMENTAL DESIGN

Epididymal WAT of four young adult rats was used to isolate adipocytes with collagenase. Careful recording of lipid content of tissue, and all fraction volumes and weights, allowed us to trace the amount of initial WAT fat remaining in the cell preparation. Functionality was estimated by incubation with glucose and measurement of glucose uptake and lactate, glycerol and NEFA excretion rates up to 48 h. Non-adipocyte cells were also recovered and their sizes (and those of adipocytes) were measured. The presence of non-nucleated cells (erythrocytes) was also estimated.

RESULTS

Cell numbers and sizes were correlated from all fractions to intact WAT. Tracing the lipid content, the recovery of adipocytes in the final, metabolically active, preparation was in the range of 70-75%. Cells showed even higher metabolic activity in the second than in the first day of incubation. Adipocytes were 7%, erythrocytes 66% and other stromal (nucleated cells) 27% of total WAT cells. However, their overall volumes were 90%, 0.05%, and 0.2% of WAT. Non-fat volume of adipocytes was 1.3% of WAT.

CONCLUSIONS

The methodology presented here allows for a direct quantitative reference to the original tissue of studies using isolated cells. We have also found that the "live cell mass" of adipose tissue is very small: about 13 µL/g for adipocytes and 2 µL/g stromal, plus about 1 µL/g blood (the rats were killed by exsanguination). These data translate (with respect to the actual "live cytoplasm" size) into an extremely high metabolic activity, which make WAT an even more significant agent in the control of energy metabolism.

Pin1 enhances adipocyte differentiation by positively regulating the transcriptional activity of PPARγ

Pin1 is a peptidylprolyl cis/trans isomerase and it has a unique enzymatic activity of catalyzing isomerization of the peptide bond between phospho-serine/threonine and proline. Through the conformational change of its substrates, Pin1 regulates diverse biological processes including adipogenesis. In mouse embryonic fibroblasts and 3T3-L1 preadipocytes, overexpression of Pin1 enhances adipocyte differentiation whereas inhibition of Pin1 activity suppresses it. However, the precise functions of Pin1 during adipogenesis are not clear. In the present study, we investigated the potential targets of Pin1 during adipogenesis. We found that Pin1 interacts directly with and regulates the transcriptional activity of PPARγ, a key regulator of adipogenesis. In addition, ERK activity and Ser273 of PPARγ, a potential ERK phosphorylation target site, are important for the regulation of PPARγ function by Pin1 in 3T3-L1 cells. Taken together our results suggest a novel regulatory mechanism of Pin1 during adipogenesis, in which Pin1 enhances adipocyte differentiation by regulating the function of PPARγ.

Aptamers: novel diagnostic and therapeutic tools for diabetes mellitus and metabolic diseases

Diabetes mellitus is one of the most common chronic diseases that threatens human health in worldwide populations. Despite enormous efforts invested in the study of diabetes mellitus, the development of precise diagnoses and treatments for this disease remains difficult due to the limitations of current techniques. Therefore, new methods are currently being developed. Aptamers are oligonucleotides that bind to specific target molecules and have been widely applied as diagnostic and therapeutic tools. In recent years, aptamers have been utilized in the study of diabetes mellitus and metabolic diseases. In this review, we highlight recent developments and new perspectives on aptamers in the field of diabetes mellitus and other metabolic diseases. Aptamers could potentially provide the means for efficient diagnoses and therapies against diabetes mellitus.

Effects of isotretinoin on body mass index, serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients

Introduction

Isotretinoin has been successfully used for the treatment of acne vulgaris.

Aim

To investigate the effects of isotretinoin on body mass index (BMI), to determine whether isotretinoin causes any changes in serum adiponectin, leptin, and ghrelin levels in acne vulgaris patients, and to correlate variables.

Material and methods

Thirty-two patients were included in this study. Oral isotretinoin was begun at a dose of 0.5–0.6 mg/kg and raised to 0.6–0.75 mg/kg. Pretreatment and posttreatment third-month BMI and adiponectin, leptin, and ghrelin serum levels were measured.

Results

The pre- and posttreatment BMI values were not significantly different. In addition, serum adiponectin and leptin levels were significantly increased following isotretinoin therapy while serum ghrelin levels were not different.

Conclusions

Isotretinoin may exert its anti-inflammatory activity by increasing leptin and adiponectin levels.

Dropping in on the lipid droplet- tumor protein D52 (TPD52) as a new regulator and resident protein

Lipid droplets are essential for both the storage and retrieval of excess cellular nutrients, and their biology is regulated by a diverse range of cellular proteins, some of which function at the lipid droplet. Numerous studies have characterized lipid droplet proteomes in different organisms and cell types, and RNAi whole genome screening studies have examined the genetic regulation of lipid storage in C. elegans and D. melanogaster. While tumor protein D52 (TPD52) did not emerge from earlier studies as a strong candidate, exogenous expression of human TPD52 in cultured cells resulted in significantly increased numbers of lipid droplets, and oleic acid supplementation increased TPD52 detection at both lipid droplets and the Golgi apparatus. These results suggest that direct testing of proteins that are infrequently but recurrently identified in proteomic and RNAi screening studies may identify novel lipid droplet regulators. While the analysis of these possibly lower-abundance or itinerant lipid droplet proteins may be more technically challenging, such proteins could facilitate a more detailed interrogation of emerging aspects of lipid droplet biology.

Vanadium(IV)-chlorodipicolinate inhibits 3T3-L1 preadipocyte adipogenesis by activating LKB1/AMPK signaling pathway

Our previous studies demonstrated that vanadium(IV) complex with 4-chlorodipicolinic acid (VOdipic-Cl) alleviates lipid abnormalities in streptozotocin (STZ)-induced diabetic rats. However, the molecular mechanisms are not fully understood. In the present study, the effect of VOdipic-Cl on adipogenesis and mechanisms of action in 3T3-L1 preadipocytes were investigated. The 3T3-L1 preadipocytes were induced to differentiate in the presence or absence of VOdipic-Cl for 8days. The cells were determined for proliferation, differentiation, lipid accumulation as well as the protein expressions of molecular targets that are involved in fatty acid synthesis. The results demonstrated that VOdipic-Cl at concentrations ranging from 2.5μM to 10μM reduced the intracellular lipid content by 10%, 22% and 30% compared to control. VOdipic-Cl down-regulated the expression of peroxisome proliferator-activated receptor (PPARγ), CCAAT element binding protein a (C/EBPα), sterol regulatory element binding protein 1c (SREBP-1c), fatty acid synthase (FAS) and fatty acid-binding protein 4 (FABP4) and activated the phosphorylation of acetyl coenzyme A carboxylase (ACC), adenosine monophosphate-activated protein kinase (AMPK) and liver kinase B1 (LKB1) in a dose-dependent manner. Further studies showed that AMPK small interfering RNA (siRNA) markedly up-regulated PPARγ, C/EBPα, FAS and FABP4 expression in the presence of VOdipic-Cl, respectively. When LKB1 was silenced with siRNA, the effect of VOdipic-Cl on AMPK phosphorylation was diminished. Taken together, these results suggested that VOdipic-Cl can inhibit 3T3-L1 preadipocyte differentiation and adipogenesis through activating the LKB1/AMPK-dependent signaling pathway. These findings raise the possibility that VOdipic-Cl may be a promising therapy in treatment of obesity.

Ameliorative potential of gingerol: Promising modulation of inflammatory factors and lipid marker enzymes expressions in HFD induced obesity in rats

Obesity, generally linked to hyperlipidemia, has been occurring of late with distressing alarm and has now become a global phenomenon casting a huge economic burden on the health care system of countries around the world. The present study investigated the effects of gingerol over 30 days on the changes in HFD-induced obese rats in marker enzymes of lipid metabolism such as fatty-acid synthase (FAS), Acetyl CoA Carboxylase (ACC), Carnitine Palmitoyl Transferase-1(CPT-1), HMG co-A Reductase (HMGR), Lecithin Choline Acyl Transferase (LCAT) and Lipoprotein Lipase (LPL) and inflammatory markers (TNF-α and IL-6). The rats were treated orally with gingerol (75 mg kg(-1)) once daily for 30 days with a lorcaserin-treated group (10 mg kg(-1)) included for comparison. Changes in body weight, glucose, insulin resistance and expressions of lipid marker enzymes and inflammatory markers in tissues were observed in experimental rats. The administration of gingerol resulted in a significant reduction in body weight gain, glucose and insulin levels, and insulin resistance, which altered the activity, expressions of lipid marker enzymes and inflammatory markers. It showed that gingerol had significantly altered these parameters when compared with HFD control rats. This study confirms that gingerol prevents HFD-induced hyperlipidemia by modulating the expression of enzymes important to cholesterol metabolism.

β-Asarone modulate adipokines and attenuates high fat diet-induced metabolic abnormalities in Wistar rats

Here we investigated the effect of β-asarone on food preference and its therapeutic potential against high fat diet (HFD) induced obesity in rats. In food preference study, free access to HFD was given only for 4h in addition to standard laboratory chow in rats and the preferential intake between chow and HFD was measured. For obesity induction, HFD was administered for 12 weeks and the HFD fed rats were treated with β-asarone in the last 4 weeks, starting from 9th week onwards. Food intake, body weight was measured biweekly. Glucose tolerance and the levels of glucose, lipids, free fatty acids, leptin, and adiponectin were assessed. HFD fed rats showed progressive increase in body weight and developed glucose intolerance and dyslipidemia. In addition, they showed increased adiposity and the disturbed pattern of adipokine levels In the food preference paradigm, β-asarone produced selective decrease in HFD intake in rats. In obese rats, β-asarone treatment not only reduced body weight but also prevented HFD-induced metabolic alterations, including glucose intolerance, dyslipidemia and adipokine imbalance. The observed beneficial effects of β-asarone appear due its ability to reduce intake of energy dense food by affecting food palatability, and to normalize the levels of leptin and adiponectin in rats. Overall, our results suggest that β-asarone is a novel candidate molecule with significant therapeutic potential in the management of obesity and associated abnormalities.

Roots extracts of Adenophora triphylla var. japonica improve obesity in 3T3-L1 adipocytes and high-fat diet-induced obese mice

OBJECTIVE

To investigate the anti-obesity activity and the action mechanism of the roots of Adenophora triphylla var. japonica extract (ATE) in high-fat diet (HFD)-induced obese mice and 3T3-L1 adipocytes.

METHODS

The roots of Adenophora triphylla were extracted with 70% ethanol. To demonstrate the compounds, linoleic acid was analyzed by using gas chromatography; and the anti-obesity effects and possible mechanisms of ATE were examined in 3T3-L1 adipocytes and HFD-induced obese mice.

RESULTS

Treatment with ATE inhibited the lipid accumulation without cytotoxicity in 3T3-L1 adipocytes. Furthermore, 200 and 400 mg/kg ATE treatment significantly decreased the body weight gain, white adipose tissues (WATs) weight and plasma triglyceride level, while 100 and 200 mg/kg ATE treatment increased the plasma high-density lipoprotein cholesterol level in the HFD-induced obese mice, as compared with the HFD group. Treatment with 200 and 400 mg/kg ATE also lowered the size of adipocytes in adipose tissue and reduced the lipid accumulation in liver. ATE treatment showed significantly lower expression level of adipogenesis-related proteins, such as peroxisome proliferator-activated receptor γ, fatty acid binding protein (aP2), fatty acid synthase in 3T3-L1 adipocytes; and furthermore, decreased peroxisome proliferator-activated receptor γ, aP2, fatty acid synthase, sterol regulatory element binding protein-1c, and lipoprotein lipase mRNA expression levels in WAT of the HFD-induced obese mice.

CONCLUSIONS

These results suggested that the ATE has an anti-obesity effect, which may be elicited by regulating the expression of adipogenesis and lipogenesis-related genes and proteins in adipocytes and WAT of the HFD-induced obese mice.

Mangosteen Extract Attenuates the Metabolic Disorders of High-Fat-Fed Mice by Activating AMPK

This study investigated the effects of mangosteen on metabolic syndromes in high-fat (HF) diet-fed mice and the underlying mechanisms related to adipogenesis. Mangosteen-supplemented mice gained significantly less body weight, compared with the HF group. The levels were markedly elevated in HF mice for serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, glucose, triglyceride, total cholesterol, low-density lipoprotein (LDL) cholesterol, and free fatty acid; whereas these levels were significantly lower in the 200 mg/kg of the mangosteen extract-treated group. The mangosteen extract did not modify high-density lipoprotein (HDL)-cholesterol, however, LDL-cholesterol was lower and HDL/LDL ratio was higher (9.4 vs. 3.7 in HF group). Furthermore, 200 mg/kg of mangosteen treatment activated the hepatic AMP-activated protein kinase and Sirtuin 1 in an in vivo system. Thus, the results of this study suggest that mangosteen extract exerts antiobesity effects by regulating energy metabolism and hepatic lipid homeostasis.

α-Mangostin Regulates Hepatic Steatosis and Obesity through SirT1-AMPK and PPARγ Pathways in High-Fat Diet-Induced Obese Mice

Previous studies have shown that α-mangostin (α-MG) suppresses intracellular fat accumulation and stimulation of lipolysis in in vitro systems. Together with the relatively high distribution of α-MG in liver and fat, these observations made it possible to propose a plausible hypothesis that an α-MG supplement may regulate hepatic steatosis and obesity. An α-MG supplement (50 mg/kg) reduced the body weight gain (13.8%) and epidymal and retroperitoneal fat mass accumulation (15.0 and 11.3%, respectively), as well as the biochemical serum profiles such as cholesterol [TC (26.9%), LDL-C (39.1%), and HDL-C (15.3%)], glucose (30.2%), triglyceride (29.7%), and fatty acid (30.3%) levels in high-fat fed mice compared with the high-fat diet-treated group, indicating that α-MG may regulate lipid metabolism. In addition, an α-MG supplement up-regulated hepatic AMPK, SirT1, and PPARγ levels compared with the high-fat diet states, suggesting that α-MG regulates hepatic steatosis and obesity through the SirT1-AMPK and PPARγ pathways in high-fat diet-induced obese mice.

Cyanidin-3-glucoside derived from black soybeans ameliorate type 2 diabetes through the induction of differentiation of preadipocytes into smaller and insulin-sensitive adipocytes

Black soybean is a health food has been reported to have antidiabetes effect. The onset of diabetes is closely associated with adipocyte differentiation, and at present, the effect of black soybean on adipocyte differentiation is unknown. Here, we investigated the antidiabetes effect of black soybean, and its anthocyanin cyanidin-3-glucoside (Cy3G), on adipocyte differentiation. Orally administered black soybean seed coat extract (BSSCE) reduced the body and white adipose tissue (WAT) weight of db/db mice accompanied by a decrease in the size of adipocytes in WAT. Furthermore, 3T3-Ll cells treated with BSSCE and Cy3G were observed to differentiate into smaller adipocytes which correlated with increased PPARγ and C/EBPα gene expressions, increased adiponectin secretion, decreased tumor necrosis factor-α secretion, activation of insulin signalling and increased glucose uptake. C2C12 myotubes cultured with conditioned medium, obtained from 3T3-L1 adipocyte cultures treated with Cy3G, also showed significantly increased expression of PGC-1α, SIRT1 and UCP-3 genes. Here we report that BSSCE, as well as its active compound Cy3G, has antidiabetes effects on db/db mice by promoting adipocyte differentiation. This notion is supported by BSSCE and Cy3G inducing the differentiation of 3T3-L1 preadipocytes into smaller, insulin-sensitive adipocytes, and it induced the activation of skeletal muscle metabolism. This is the first report on the modulation effect of Cy3G on adipocyte differentiation.

Comprehensive biometric, biochemical and histopathological assessment of nutrient deficiencies in gilthead sea bream fed semi-purified diets

Seven isoproteic and isolipidic semi-purified diets were formulated to assess specific nutrient deficiencies in sulphur amino acids (SAA), n-3 long-chain PUFA (n-3 LC-PUFA), phospholipids (PL), P, minerals (Min) and vitamins (Vit). The control diet (CTRL) contained these essential nutrients in adequate amounts. Each diet was allocated to triplicate groups of juvenile gilthead sea bream fed to satiety over an 11-week feeding trial period. Weight gain of n-3 LC-PUFA, P-Vit and PL-Min-SAA groups was 50, 60-75 and 80-85 % of the CTRL group, respectively. Fat retention was decreased by all nutrient deficiencies except by the Min diet. Strong effects on N retention were found in n-3 LC-PUFA and P fish. Combined anaemia and increased blood respiratory burst were observed in n-3 LC-PUFA fish. Hypoproteinaemia was found in SAA, n-3 LC-PUFA, PL and Vit fish. Derangements of lipid metabolism were also a common disorder, but the lipodystrophic phenotype of P fish was different from that of other groups. Changes in plasma levels of electrolytes (Ca, phosphate), metabolites (creatinine, choline) and enzyme activities (alkaline phosphatase) were related to specific nutrient deficiencies in PL, P, Min or Vit fish, whereas changes in circulating levels of growth hormone and insulin-like growth factor I primarily reflected the intensity of the nutritional stressor. Histopathological scoring of the liver and intestine segments showed specific nutrient-mediated changes in lipid cell vacuolisation, inflammation of intestinal submucosa, as well as the distribution and number of intestinal goblet and rodlet cells. These results contribute to define the normal range of variation for selected biometric, biochemical, haematological and histochemical markers.

α-Mangostin Improves Glucose Uptake and Inhibits Adipocytes Differentiation in 3T3-L1 Cells via PPARγ, GLUT4, and Leptin Expressions

Obesity has been often associated with the occurrence of cardiovascular diseases, type 2 diabetes, and cancer. The development of obesity is also accompanied by significant differentiation of preadipocytes into adipocytes. In this study, we investigated the activity of α-mangostin, a major xanthone component isolated from the stem bark of G. malaccensis, on glucose uptake and adipocyte differentiation of 3T3-L1 cells focusing on PPARγ, GLUT4, and leptin expressions. α-Mangostin was found to inhibit cytoplasmic lipid accumulation and adipogenic differentiation. Cells treated with 50 μM of α-mangostin reduced intracellular fat accumulation dose-dependently up to 44.4% relative to MDI-treated cells. Analyses of 2-deoxy-D-[(3)H] glucose uptake activity showed that α-mangostin significantly improved the glucose uptake (P < 0.05) with highest activity found at 25 μM. In addition, α-mangostin increased the amount of free fatty acids (FFA) released. The highest glycerol release level was observed at 50 μM of α-mangostin. qRT-PCR analysis showed reduced lipid accumulation via inhibition of PPARγ gene expression. Induction of glucose uptake and free fatty acid release by α-mangostin were accompanied by increasing mRNA expression of GLUT4 and leptin. These evidences propose that α-mangostin might be possible candidate for the effective management of obesity in future.

Oligopeptide complex for targeted non-viral gene delivery to adipocytes

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.

Two novel polymorphisms of bovine SIRT2 gene are associated with higher body weight in Nanyang cattle

Identification of polymorphisms associated with economic traits is important for successful marker-assisted selection in cattle breeding. The family of mammalian sirtuin regulates many biological functions, such as life span extension and energy metabolism. SIRT2, a most abundant sirtuin in adipocytes, acts as a crucial regulator of adipogenic differentiation and plays a key role in controlling adipose tissue function and mass. Here we investigated single nucleotide polymorphisms (SNPs) of bovine SIRT2 in 1226 cattle from five breeds and further evaluated the effects of identified SNPs on economically important traits of Nanyang cattle. Our results revealed four novel SNPs in bovine SIRT2, one was located in intronic region and the other three were synonymous mutations. Linkage disequilibrium and haplotype analyses based on the identified SNPs showed obvious difference between crossbred breed and the other four beef breeds. Association analyses demonstrated that SNPs g.17333C > T and g.17578A > G have a significantly effect on 18-months-old body weight of Nanyang population. Animals with combined genotype TTGG at the above two loci exhibited especially higher body weight. Our data for the first time demonstrated that polymorphisms in bovine SIRT2 are associated with economic traits of Nanyang cattle, which will be helpful for future cattle selection practices.

Brown, beige, and white: the new color code of fat and its pharmacological implications

Brown adipose tissue (BAT) was previously regarded as a special type of fat relevant only for defending hibernating animals and newborns against a cold environment. Recently, BAT has received considerable attention following its (re)discovery in humans. Using glucose tracers, multiple laboratories independently found metabolically active BAT in adults. The enormous metabolic powers of BAT in animal models could make it an attractive target for antiobesity therapies in humans. Here, we review the present knowledge on the role of BAT in energy homeostasis and metabolism, focusing on signaling pathways and potential targets for novel therapeutics. We also shine light on ongoing debates, including those about the true color of brown fat in adults, as well as on the requirements for translation of basic research on BAT into clinical medicine.

Zinc-chelated Vitamin C Stimulates Adipogenesis of 3T3-L1 Cells

Adipose tissue development and function play a critical role in the regulation of energy balance, lipid metabolism, and the pathophysiology of metabolic syndromes. Although the effect of zinc ascorbate supplementation in diabetes or glycemic control is known in humans, the underlying mechanism is not well described. Here, we investigated the effect of a zinc-chelated vitamin C (ZnC) compound on the adipogenic differentiation of 3T3-L1 preadipocytes. Treatment with ZnC for 8 d significantly promoted adipogenesis, which was characterized by increased glycerol-3-phosphate dehydrogenase activity and intracellular lipid accumulation in 3T3-L1 cells. Meanwhile, ZnC induced a pronounced up-regulation of the expression of glucose transporter type 4 (GLUT4) and the adipocyte-specific gene adipocyte protein 2 (aP2). Analysis of mRNA and protein levels further showed that ZnC increased the sequential expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), the key transcription factors of adipogenesis. These results indicate that ZnC could promote adipogenesis through PPARγ and C/EBPα, which act synergistically for the expression of aP2 and GLUT4, leading to the generation of insulin-responsive adipocytes and can thereby be useful as a novel therapeutic agent for the management of diabetes and related metabolic disorders.

Phosphorylation of histone H2AX in the mouse brain from development to senescence

Phosphorylation of the histone H2AX (γH2AX form) is an early response to DNA damage and a marker of aging and disease in several cells and tissues outside the nervous system. Little is known about in vivo phosphorylation of H2AX in neurons, although it was suggested that γH2AX is an early marker of neuronal endangerment thus opening the possibility to target it as a neuroprotective strategy. After experimental labeling of DNA-synthesizing cells with 5-bromo-2-deoxyuridine (BrdU), we studied the brain occurrence of γH2AX in developing, postnatal, adult and senescent (2 years) mice by light and electron microscopic immunocytochemistry and Western blotting. Focal and/or diffuse γH2AX immunostaining appears in interkinetic nuclei, mitotic chromosomes, and apoptotic nuclei. Immunoreactivity is mainly associated with neurogenetic areas, i.e., the subventricular zone (SVZ) of telencephalon, the cerebellar cortex, and, albeit to a much lesser extent, the subgranular zone of the hippocampal dentate gyrus. In addition, γH2AX is highly expressed in the adult and senescent cerebral cortex, particularly the piriform cortex. Double labeling experiments demonstrate that γH2AX in neurogenetic brain areas is temporally and functionally related to proliferation and apoptosis of neuronal precursors, i.e., the type C transit amplifying cells (SVZ) and the granule cell precursors (cerebellum). Conversely, γH2AX-immunoreactive cortical neurons incorporating the S phase-label BrdU do not express the proliferation marker phosphorylated histone H3, indicating that these postmitotic cells undergo a significant DNA damage response. Our study paves the way for a better comprehension of the role of H2AX phosphorylation in the normal brain, and offers additional data to design novel strategies for the protection of neuronal precursors and mature neurons in central nervous system (CNS) degenerative diseases.

Detecting protein carbonylation in adipose tissue and in cultured adipocytes

Reactive oxygen species-mediated attack of the acyl chains of polyunsaturated fatty acids and triglycerides leads to the formation of lipid hydroperoxides. Lipid hydroperoxides are subject to nonenzymatic Fenton chemistry producing a variety of reactive aldehydes that covalently modify proteins in a reaction referred to as protein carbonylation. Given the significant content of triglycerides in fat tissue, adipose proteins are among the most heavily carbonylated. The laboratory has utilized two methodologies for the detection of protein carbonylation in tissue- and cell-based samples. The first utilizes biotin coupled to a hydrazide moiety and takes advantage of the numerous biotin detection systems. The second method utilizes an anti 4-hydroxy-trans-2,3-nonenal (4-HNE)-directed antibody that can detect both 4-HNE and the corresponding 4-oxo derivative when the samples are reduced. Using such methods, we have evaluated the profile of carbonylated proteins in epididymal white adipose tissue and 3T3-L1 adipocytes using both methods. In addition, we have investigated the effects of two antidiabetic drugs, pioglitazone and metformin, on protein carbonylation in 3T3-L1 adipocytes. Overall, the biotin hydrazide method is rapid, inexpensive, and easy to use, but its usefulness is limited because it detects a wide variety of carbonylated derivatives, which makes assignments of individual proteins difficult. Compared to the biotin hydrazide method, the anti-HNE antibody method detects specific proteins more readily but identifies only a subset of carbonylated proteins. As such, the combination of both methods allows for a comprehensive evaluation of protein carbonylation plus provides a means towards identification of specific carbonylation targets.

Lucidone from Lindera erythrocarpa Makino fruits suppresses adipogenesis in 3T3-L1 cells and attenuates obesity and consequent metabolic disorders in high-fat diet C57BL/6 mice

Obesity is associated with an increased risk of development of numerous diseases including type 2 diabetes, hypertension, hyperlipidemia, and cardiovascular disease. In this study, we investigated the effects of lucidone in vitro on gene expression during adipogenesis in 3T3-L1 cells and in vivo on high-fat diet induced obesity in C57BL/6 mice. Lucidone at 40 μmol/L suppressed adipogenesis in 3T3-L1 cells by reducing transcription levels of adipogenic genes, including PPARγ, C/EBPα, LXR-α, LPL, aP2, GLUT4 and adiponectin. Five-week-old male C57BL/6 mice fed a high fat diet (60% energy from fat) supplemented with lucidone at a dosage of 1250 mg/kg of diet for 12 weeks had reduced body and liver weight, reduced epididymal and perirenal adipose tissue, decreased food efficiency (percentage of weight gain divided by food intake), and lowered plasma cholesterol, triglyceride, glucose, and insulin levels. Dissection of adipose tissue from lucidone-treated mice showed a reduction in the average fat-cell size and percentage of large adipocytes. These results provide evidence that dietary intake of lucidone alleviates high fat diet-induced obesity in C57BL/6 mice and reveals the potential of lucidone as a nutraceutical to prevent obesity and consequent metabolic disorders.

Overexpression of C10orf116 promotes proliferation, inhibits apoptosis and enhances glucose transport in 3T3-L1 adipocytes

Data from our previous study demonstrated that C10orf116 is an adipocyte lineage-specific nuclear factor, which regulates master adipogenesis transcription factors during early differentiation. However, the precise functional properties of this gene have yet to be identified and further investigation is required. In the present study, we report the effects of C10orf116 expression on cell proliferation and apoptosis in vitro and observed that the overexpression of C10orf116 stimulates proliferation and inhibits apoptosis in preadipocytes. Furthermore, we investigated the effects of C10orf116 on glucose uptake and demonstrated that the ectopic expression of C10orf116 significantly increases insulin-stimulated glucose uptake in adipocytes by increasing glucose transporter type 4 (GLUT4) expression levels. Collectively, these data further support the hypothesis that C10orf116 is important in regulating glucose transport in adipocytes as well as the number of preadipocytes. The results of the present study may also provide insights into the complex mechanisms involved in the development of obesity.