Role of PPARgamma, transcriptional cofactors, and adiponectin in the regulation of nutrient metabolism, adipogenesis and insulin action: view from the chair

Exploring the Gut Microbiome in Myasthenia Gravis

The human gut microbiota is vital for maintaining human health in terms of immune system homeostasis. Perturbations in the composition and function of microbiota have been associated with several autoimmune disorders, including myasthenia gravis (MG), a neuromuscular condition associated with varying weakness and rapid fatigue of the skeletal muscles triggered by the host’s antibodies against the acetylcholine receptor (AChR) in the postsynaptic muscle membrane at the neuromuscular junction (NMJ). It is hypothesized that perturbation of the gut microbiota is associated with the pathogenesis of MG. The gut microbiota community profiles are usually generated using 16S rRNA gene sequencing. Compared to healthy individuals, MG participants had an altered gut microbiota’s relative abundance of bacterial taxa, particularly with a drop in Clostridium. The microbial diversity related to MG severity and the overall fecal short-chain fatty acids (SCFAs) were lower in MG subjects. Changes were also found in terms of serum biomarkers and fecal metabolites. A link was found between the bacterial Operational Taxonomic Unit (OTU), some metabolite biomarkers, and MG’s clinical symptoms. There were also variations in microbial and metabolic markers, which, in combination, could be used as an MG diagnostic tool, and interventions via fecal microbiota transplant (FMT) could affect MG development. Probiotics may influence MG by restoring the gut microbiome imbalance, aiding the prevention of MG, and lowering the risk of gut inflammation by normalizing serum biomarkers. Hence, this review will discuss how alterations of gut microbiome composition and function relate to MG and the benefits of gut modulation.

Key signaling networks are dysregulated in patients with the adipose tissue disorder, lipedema

Objectives

Lipedema, a poorly understood chronic disease of adipose hyper-deposition, is often mistaken for obesity and causes significant impairment to mobility and quality-of-life. To identify molecular mechanisms underpinning lipedema, we employed comprehensive omics-based comparative analyses of whole tissue, adipocyte precursors (adipose-derived stem cells (ADSCs)), and adipocytes from patients with or without lipedema.

Methods

We compared whole-tissues, ADSCs, and adipocytes from body mass index–matched lipedema (n = 14) and unaffected (n = 10) patients using comprehensive global lipidomic and metabolomic analyses, transcriptional profiling, and functional assays.

Results

Transcriptional profiling revealed >4400 significant differences in lipedema tissue, with altered levels of mRNAs involved in critical signaling and cell function-regulating pathways (e.g., lipid metabolism and cell-cycle/proliferation). Functional assays showed accelerated ADSC proliferation and differentiation in lipedema. Profiling lipedema adipocytes revealed >900 changes in lipid composition and >600 differentially altered metabolites. Transcriptional profiling of lipedema ADSCs and non-lipedema ADSCs revealed significant differential expression of >3400 genes including some involved in extracellular matrix and cell-cycle/proliferation signaling pathways. One upregulated gene in lipedema ADSCs, Bub1, encodes a cell-cycle regulator, central to the kinetochore complex, which regulates several histone proteins involved in cell proliferation. Downstream signaling analysis of lipedema ADSCs demonstrated enhanced activation of histone H2A, a key cell proliferation driver and Bub1 target. Critically, hyperproliferation exhibited by lipedema ADSCs was inhibited by the small molecule Bub1 inhibitor 2OH-BNPP1 and by CRISPR/Cas9-mediated Bub1 gene depletion.

Conclusion

We found significant differences in gene expression, and lipid and metabolite profiles, in tissue, ADSCs, and adipocytes from lipedema patients compared to non-affected controls. Functional assays demonstrated that dysregulated Bub1 signaling drives increased proliferation of lipedema ADSCs, suggesting a potential mechanism for enhanced adipogenesis in lipedema. Importantly, our characterization of signaling networks driving lipedema identifies potential molecular targets, including Bub1, for novel lipedema therapeutics.

Exploring the Genetic Conception of Obesity via the Dual Role of FoxO

Obesity or overweight are not superficial problems, constituting a pressing issue. The obesity index has almost tripled since 1975, which is an alarming state. Most of the individuals are currently becoming overweight or have inappropriate body mass index (BMI) conditions. Obesity is characterized by increased fat accumulation and thus poses a higher health risk. There is increased size and volume of fat cells in the body, which usually accounts for obesity. Many investigations have been carried out in this area, such as behavioral improvements, dietary changes, chemical involvements, etc., but presently no such goals are established to manage these health concerns. Based on previous literature reports and our interpretation, the current review indicates the involvement of various transcriptional and transporter functions in modifying the above-mentioned health conditions. Various transcriptional factors such as Forkhead box O1 (FoxO1) impart a significant effect on the physiology and pathology of metabolic dysfunction such as obesity. FoxO1 plays a dual role whether in the progression or suppression of metabolic processes depending on its targets. Thus, in the current study, will be discussed the dual role of FoxO1 in metabolic conditions (such as obesity), also summarizing the role of various other transcriptional factors involved in obesity.

Exploring the Genetic Conception of Obesity via the Dual Role of FoxO

Obesity or overweight are not superficial problems, constituting a pressing issue. The obesity index has almost tripled since 1975, which is an alarming state. Most of the individuals are currently becoming overweight or have inappropriate body mass index (BMI) conditions. Obesity is characterized by increased fat accumulation and thus poses a higher health risk. There is increased size and volume of fat cells in the body, which usually accounts for obesity. Many investigations have been carried out in this area, such as behavioral improvements, dietary changes, chemical involvements, etc., but presently no such goals are established to manage these health concerns. Based on previous literature reports and our interpretation, the current review indicates the involvement of various transcriptional and transporter functions in modifying the above-mentioned health conditions. Various transcriptional factors such as Forkhead box O1 (FoxO1) impart a significant effect on the physiology and pathology of metabolic dysfunction such as obesity. FoxO1 plays a dual role whether in the progression or suppression of metabolic processes depending on its targets. Thus, in the current study, will be discussed the dual role of FoxO1 in metabolic conditions (such as obesity), also summarizing the role of various other transcriptional factors involved in obesity.

Pathophysiology of high fat diet induced obesity: impact of probiotic banana juice on obesity associated complications and hepatosteatosis

The high fat diet alters intestinal microbiota due to increased intestinal permeability and susceptibility to microbial antigens leads to metabolic endotoxemia. But probiotic juices reported for various health benefits. In this background we hypothesized that pectinase treated probiotic banana juice has diverse effects on HFD induced obesity and non-alcoholic steatohepatitis. 20 weeks fed HFD successfully induced obesity and its associated complications in experimental rats. The supplementation of probiotic banana juice for 5 months at a dose of 5 mL/kg bw/day resulted significant decrease (p < 0.05) in body weight (380 ± 0.34), total fat (72 ± 0.8), fat percentage (17 ± 0.07) and fat free mass (165 ± 0.02). Reduction (p < 0.05) in insulin resistance (5.20 ± 0.03), lipid profile (TC 120 ± 0.05; TG 160 ± 0.24; HDL 38 ± 0.03), liver lipid peroxidation (0.7 ± 0.01), hepatic enzyme markers (AST 82 ± 0.06; ALT 78 ± 0.34; ALP 42 ± 0.22), and hepatic steatosis by increasing liver antioxidant potential (CAT 1.4 ± 0.30; GSH 1.04 ± 0.04; SOD 0.82 ± 0.22) with normal hepatic triglycerides (15 ± 0.02) and glycogen (0.022 ± 0.15) contents and also showed normal liver size, less accumulation of lipid droplets with only a few congestion. It is concluded that the increased intestinal S. cerevisiae yeast can switch anti-obesity, antidiabetic, antioxidative stress, antioxidant and anti-hepatosteatosis effect. This study results will have significant implications for treatment of NAFLD.

Urinary bisphenol A and thyroid function by BMI in the Korean National Environmental Health Survey (KoNEHS) 2012-2014

Bisphenol A (BPA) is one of the largest amounts of chemicals in daily life and source of polycarbonate plastics, epoxy resins, medical equipment, plastic consumer products. Recent studies reported that the effects of BPA on human health in the thyroid hormone. Therefore, this study aimed to indicate the association between urinary BPA concentration and thyroid function in total triiodothyronine (T3), thyroxine (T4), thyroidal stimulating hormone (TSH) and stratified the population by body mass index (BMI). This study was performed on 6478 adults aged 19 years and older based on the Second Korean National Environmental Health Survey (KoNEHS, 2012-2014). We measured BPA in urine and total T3, T4 and TSH in serum from the 2nd KoNEHS study. The multiple regression analysis was performed to assess the association of urinary BPA concentrations with thyroid hormone after BMI stratification. Urinary BPA associated with thyroid hormone. Especially, BPA is related to T3 (-0.627) in all group, and T4 (-0.060, -0.098) in all group and the group of BMI 25.0kg/m2 or more negatively. When stratified by BPA, T3 and T4 were significantly decreased with the high BPA exposure compared with the low BPA exposure for BMI more than 25.0kg/m2 (adjusted β = -3.402, 95% CI: 4.942, -1.862, adjusted β = -0.209, 95% CI: 0.328, -0.090). However, no obvious associations were found between BPA concentration and TSH. The results of urinary BPA decrease with T3 and T4 levels increase in the higher BMI group is a new finding which does not exist in recent studies of Korea.

Up-regulation of bone morphogenetic protein and its signaling molecules following castration of bulls and their association with intramuscular fat content in Korean cattle

We evaluated whether castration affects bone morphogenetic protein 2 (BMP2) level and the expression of its signaling molecules in Korean cattle bulls. We also checked whether castration affects the expression of muscle fiber type and oxidative and glycolytic enzyme genes. Enzyme-linked immunosorbent assays revealed that steers had higher plasma BMP2 and leptin concentrations than bulls. Quantitative real-time PCR showed that steers had higher mRNA levels of the lysyl oxidase gene, a downstream target of the BMP signaling pathway, in the longissimus thoracis (LT) muscle. Steers had higher adipogenic peroxisome proliferator-activated receptor gamma and lipogenic fatty acid binding protein 4 mRNA levels in the LT than bulls. Steers had lower mRNA levels for several muscle fiber type 1 genes and fiber type 2A myosin heavy chain 2 gene than bulls. Steers had higher mRNA levels of the glycolytic enzyme phosphoglycerate kinase 1 gene than bulls. Transcript levels of oxidative enzyme genes did not differ between bulls and steers. Regression analysis revealed a positive association between plasma BMP2 levels and intramuscular fat (IMF) content in the steer group. These findings suggest that upregulation of the BMP signaling pathway in response to castration induces increased adipogenic gene expression, contributing to the increased IMF deposition observed in castrated animals.

Regulatory Efficacy of Spirulina platensis Protease Hydrolyzate on Lipid Metabolism and Gut Microbiota in High-Fat Diet-Fed Rats

Lipid metabolism disorder (LMD) is a public health issue. Spirulina platensis is a widely used natural weight-reducing agent and Spirulina platensis is a kind of protein source. In the present study, we aimed to evaluate the effect of Spirulina platensis protease hydrolyzate (SPPH) on the lipid metabolism and gut microbiota in high-fat diet (HFD)-fed rats. Our study showed that SPPH decreased the levels of triglyceride (TG), total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-c), alanine transaminase (ALT), and aspartate transaminase (AST), but increased the level of high-density-lipoprotein cholesterol (HDL-c) in serum and liver. Moreover, SPPH had a hypolipidemic effect as indicated by the down-regulation of sterol regulatory element-binding transcription factor-1c (SREBP-1c), acetyl CoA carboxylase (ACC), SREBP-1c, and peroxisome proliferator-activated receptor-γ (PPARγ) and the up-regulation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) and peroxisome proliferator-activated receptorα (PPARα) at the mRNA level in liver. SPPH treatment enriched the abundance of beneficial bacteria. In conclusion, our study showed that SPPH might be produce glucose metabolic benefits in rats with diet-induced LMD. The mechanisms underlying the beneficial effects of SPPH on the metabolism remain to be further investigated. Collectively, the above-mentioned findings illustrate that Spirulina platensis peptides have the potential to ameliorate lipid metabolic disorders, and our data provides evidence that SPPH might be used as an adjuvant therapy and functional food in obese and diabetic individuals.

Heme oxygenase-1 induction by rosiglitazone via PKCα/AMPKα/p38 MAPKα/SIRT1/PPARγ pathway suppresses lipopolysaccharide-mediated pulmonary inflammation

HO-1 (heme oxygenase-1), an antioxidant enzyme, induced by rosiglitazone (PPAR ligands) can be a potential treatment of inflammation. However, the mechanisms of rosiglitazone-induced HO-1 expression in human pulmonary alveolar epithelial cells (HPAEpiCs) remain largely unknown. In this study, we found that upregulation of HO-1 in vitro or in vivo by rosiglitazone attenuated VCAM-1 gene expression and monocyte adhesion to HPAEpiCs challenged with lipopolysaccharide (LPS). The inhibitory effects of rosiglitazone on LPS-mediated responses were reversed by transfection with HO-1 siRNA. LPS-induced VCAM-1 expression was mediated through NF-κB activation which was attenuated by rosiglitazone via suppressing p65 activation and translocation into the nucleus. Moreover, pretreatment with the inhibitor of PKCs (H7), PKCα (Gö6976), AMPKα (Compound C), p38 MAPKα (p38i VIII), SIRT1 (Sirtinol), or PPARγ (T0070907) and transfection with siRNA of PKCα, AMPKα, p38 MAPKα, SIRT1, or PPARγ abolished the rosiglitazone-induced HO-1 expression in HPAEpiCs. Further studies indicated that rosiglitazone stimulated SIRT1 deacetylase leading to PGC1α translocation from the cytosol into the nucleus, promoting fragmentation of NCoR and phosphorylation of PPARγ. Subsequently, PPARγ was activated by phosphorylation of PKCα, AMPKα, p38 MAPKα, and SIRT1, which turned on transcription of HO-1 gene by binding to PPAR response element (PPRE) and enhancing PPARγ promoter activity. These results suggested that rosiglitazone-induced HO-1 expression is mediated through PKCα/AMPKα/p38 MAPKα/SIRT1-dependent deacetylation of Ac-PGC1α and fragmentation of NCoR/PPARγ activation in HPAEpiCs. Up-regulation of HO-1 protected against the inflammatory responses triggered by LPS, at least in part, through attenuation of NF-κB.

PPAR-γ Agonists As Antineoplastic Agents in Cancers with Dysregulated IGF Axis

It is now widely accepted that insulin resistance and compensatory hyperinsulinemia are associated to increased cancer incidence and mortality. Moreover, cancer development and progression as well as cancer resistance to traditional anticancer therapies are often linked to a deregulation/overactivation of the insulin-like growth factor (IGF) axis, which involves the autocrine/paracrine production of IGFs (IGF-I and IGF-II) and overexpression of their cognate receptors [IGF-I receptor, IGF-insulin receptor (IR), and IR]. Recently, new drugs targeting various IGF axis components have been developed. However, these drugs have several limitations including the occurrence of insulin resistance and compensatory hyperinsulinemia, which, in turn, may affect cancer cell growth and survival. Therefore, new therapeutic approaches are needed. In this regard, the pleiotropic effects of peroxisome proliferator activated receptor (PPAR)-γ agonists may have promising applications in cancer prevention and therapy. Indeed, activation of PPAR-γ by thiazolidinediones (TZDs) or other agonists may inhibit cell growth and proliferation by lowering circulating insulin and affecting key pathways of the Insulin/IGF axis, such as PI3K/mTOR, MAPK, and GSK3-β/Wnt/β-catenin cascades, which regulate cancer cell survival, cell reprogramming, and differentiation. In light of these evidences, TZDs and other PPAR-γ agonists may be exploited as potential preventive and therapeutic agents in tumors addicted to the activation of IGF axis or occurring in hyperinsulinemic patients. Unfortunately, clinical trials using PPAR-γ agonists as antineoplastic agents have reached conflicting results, possibly because they have not selected tumors with overactivated insulin/IGF-I axis or occurring in hyperinsulinemic patients. In conclusion, the use of PPAR-γ agonists in combined therapies of IGF-driven malignancies looks promising but requires future developments.

Physical training and weight loss in dogs lead to transcriptional changes in genes involved in the glucose-transport pathway in muscle and adipose tissues

Obesity is a worldwide problem in humans and domestic animals. Interventions, including a combination of dietary management and exercise, have proven to be effective for inducing weight loss in humans. In companion animals, the role of exercise in the management of obesity has received relatively little attention. The aim of the present study was to investigate changes in the transcriptome of key energy metabolism genes in muscle and adipose tissues in response to diet-induced weight loss alone, or combined with exercise in dogs. Overweight pet dogs were enrolled on a weight loss programme, based on calorie restriction and physical training (FD group, n = 5) or calorie restriction alone (DO group, n = 7). mRNA expression of 12 genes and six microRNAs were investigated using quantitative real-time PCR (qPCR). In the FD group, FOXO1 and RAC1 were expressed at lower levels in adipose tissue, whereas ESRRA and AKT2 were more highly expressed in muscle, when compared with the DO group. Comparing expression before and after the intervention, in the DO group, nine genes and three microRNAs showed significant altered expression in adipose tissue (PPARG, ADIPOQ and FOXO1; P < 0.001) and seven genes and two microRNAs were significantly downregulated (NRF2, RAC1, ESRRA, AKT2, PGC1a and mir-23; P < 0.001) in muscle. Thus, calorie restriction causes regulation of several metabolic genes in both tissues. The mild exercise, incorporated into this study design, was sufficient to elicit transcriptional changes in adipose and muscle tissues, suggesting a positive effect on glucose metabolism. The study findings support inclusion of exercise in management of canine obesity.

Umbelliferone Improves an Impaired Glucose and Lipid Metabolism in High-Fat Diet/Streptozotocin-Induced Type 2 Diabetic Rats

Umbelliferone (UMB) is a natural product that has several pharmacological effects including antihyperglycemic activity in diabetic rats. Thus, the objective of this study was to investigate the effect of UMB on insulin resistance and on the regulation of glucose and lipid metabolism in type 2 diabetic rats. Type 2 diabetes was induced in rats by feeding a high-fat diet (45 kcal% fat) and a single dose of streptozotocin injection. After 8 weeks of treatment, UMB significantly reduced the elevated blood glucose levels and insulin resistance and increased the liver glycogen and serum adiponectin. Moreover, the serum lipid and the storages of triglyceride and non-esterified fatty acid in liver tissue were reduced. From histological examination, the lipid droplets in liver tissue were clearly decreased, and the fat cell size in the fat tissue was smaller in diabetic rats treated with UMB. Interestingly, UMB increased fat cell adiponectin, plasma membrane glucose transporter 4 (GLUT4) and peroxisome proliferator-activated receptor gamma (PPARγ), and liver PPARα protein expressions. Our findings demonstrate that UMB improves glucose and lipid metabolism in type 2 diabetes by stimulating the insulin secretion and the related mechanisms via stimulating expression of adiponectin, GLUT4, PPARγ, and PPARα-protein expressions. Copyright © 2015 John Wiley & Sons, Ltd.

Commensal Streptococcus salivarius Modulates PPARγ Transcriptional Activity in Human Intestinal Epithelial Cells

The impact of commensal bacteria in eukaryotic transcriptional regulation has increasingly been demonstrated over the last decades. A multitude of studies have shown direct effects of commensal bacteria from local transcriptional activity to systemic impact. The commensal bacterium Streptococcus salivarius is one of the early bacteria colonizing the oral and gut mucosal surfaces. It has been shown to down-regulate nuclear transcription factor (NF-кB) in human intestinal cells, a central regulator of the host mucosal immune system response to the microbiota. In order to evaluate its impact on a further important transcription factor shown to link metabolism and inflammation in the intestine, namely PPARγ (peroxisome proliferator-activated receptor), we used human intestinal epithelial cell-lines engineered to monitor PPARγ transcriptional activity in response to a wide range of S. salivarius strains. We demonstrated that different strains from this bacterial group share the property to inhibit PPARγ activation independently of the ligand used. First attempts to identify the nature of the active compounds showed that it is a low-molecular-weight, DNase-, proteases- and heat-resistant metabolite secreted by S. salivarius strains. Among PPARγ-targeted metabolic genes, I-FABP and Angptl4 expression levels were dramatically reduced in intestinal epithelial cells exposed to S. salivarius supernatant. Both gene products modulate lipid accumulation in cells and down-regulating their expression might consequently affect host health. Our study shows that species belonging to the salivarius group of streptococci impact both host inflammatory and metabolic regulation suggesting a possible role in the host homeostasis and health.

Evaluation of anti-obesity activities of ethanolic extract of Terminalia paniculata bark on high fat diet-induced obese rats

BACKGROUND

The prevalence and severity of obesity and associated co-morbidities are rapidly increasing across the world. Natural products-based drug intervention has been proposed as one of the crucial strategies for management of obesity ailments. This study was designed to investigate the anti-obesity activities of ethanolic extract of Terminalia paniculata bark (TPEE) on high fat diet-induced obese rats.

METHODS

LC-MS/MS analysis was done for ethanolic extract of T. paniculata bark. Male Sprague-Dawley (SD) rats were randomly divided into six groups of six each, normal diet fed (NC), high fat diet-fed (HFD), HFD+ orlistat (standard drug control) administered, and remaining three groups were fed with HFD + TPEE in different doses (100,150 and 200 mg/kg b. wt). For induction of obesity rats were initially fed with HFD for 9 weeks, then, (TPEE) was supplemented along with HFD for 42 days. Changes in body weight, body composition, blood glucose, insulin, tissue and serum lipid profiles, atherogenic index, liver markers, and expression of adipogenesis-related genes such as leptin, adiponectin, FAS, PPARgamma, AMPK-1alpha and SREBP-1c, were studied in experimental rats. Also, histopathological examination of adipose tissue was carried out.

RESULTS

Supplementation of TPEE reduced significantly (P < 0.05) body weight, total fat, fat percentage, atherogenic index, blood glucose, insulin, lipid profiles and liver markers in HFD-fed groups, in a dose-dependent manner. The expression of adipogenesis-related genes such as Leptin, FAS, PPARgamma, and SREBP-1c were down regulated while Adiponectin and AMPK-1alpha were up regulated in TPEE + HFD-fed rats. Furthermore, histopathological examination of adipose tissue revealed the alleviating effect of TPEE which is evident by reduced size of adipocytes.

CONCLUSIONS

Together, the biochemical, histological and molecular studies unambiguously demonstrate the potential anti adipogenic and anti obesity activities of TPEE promoting it as a formidable candidate to develop anti obesity drug.

Bisphenol A exposure and associations with obesity among adults: a critical review

Objective

To review the literature on bisphenol A (BPA) exposure and obesity in human populations.

Design

Systematic review of the literature via searches of PubMed, EMBASE, Web of Science and reference lists for articles published to 1 August 2014.

Setting

China, Italy, Japan, Republic of Korea, Sweden, UK, USA.

Subjects

Adults (≥18 years).

Results

Eighteen articles were identified and included in the review. Twelve studies included secondary evaluations of BPA exposure and BMI, and six studies evaluated body composition as the primary outcome. All analyses were cross-sectional and no study included in the review received a positive quality rating (twelve negative, six neutral). Eight studies observed a statistically significant positive association between urinary or serum BPA levels and BMI, and ten studies observed no association. Studies where BMI was a primary outcome and studies of neutral quality were more likely to observe an association.

Conclusions

Study results are conflicting and significant methodological issues limit the ability to draw conclusions from these studies. Prospective studies that measure BPA exposure and changes in body weight and composition are needed to establish temporality, causality and the direction of any observed associations.

A high multivitamin diet fed to Wistar rat dams during pregnancy increases maternal weight gain later in life and alters homeostatic, hedonic and peripheral regulatory systems of energy balance

High multivitamin (10-fold, HV) and high folic acid (Fol) diets fed to pregnant Wistar rats increase body weight and characteristics of the metabolic syndrome in their offspring. Our objective was to determine the effects of a HV maternal diet on dams and whether methyl vitamins contribute to these effects. Pregnant Wistar rats were fed AIN-93G diets containing either (1) recommended multivitamins (RV, control), (2) HV, (3) HV with recommended Fol (HVRF; 1-fold Fol), or (4) RV with high methyl group vitamins (HMethyl; 10-fold Fol, vitamin B12 and B6). All groups were fed a RV diet during lactation until weaning and a RV high fat (HF; 60% fat) diet for 16 weeks post-weaning. The HV, HVRF and HMethyl diet fed dams gained 45% more weight from 2 to 15 weeks post-weaning and their weight gain (WG) was positively associated with cumulative post-weaning food intake (FI). However, only HV dams had a reduced preference for a sucrose solution, lower mesolimbic dopamine (DA) turnover in the nucleus accumbens (NAc), and higher expression of several genes involved in FI regulation in the arcuate nucleus of the hypothalamus (ARC). Energy conserving peroxisome proliferator-activated receptor (Ppar)-γ in adipose and -α in liver was also greater in these dams consistent with their WG. In conclusion, HV, HVRF and HMethyl maternal diets exacerbate maternal WG when dams are exposed to a HF diet post-weaning. However, the diets differed in their effects on central and peripheral regulatory systems of energy balance.

Terminalia paniculata bark extract attenuates non-alcoholic fatty liver via down regulation of fatty acid synthase in high fat diet-fed obese rats

Background

This study was performed to understand the possible therapeutic activity of Terminalia paniculata ethanolic extract (TPEE) on non alcoholic fatty liver in rats fed with high fat diet.

Methods

Thirty six SD rats were divided into 6 groups (n = 6): Normal control (NC), high fat diet (HFD), remaining four groups were fed on HFD along with different doses of TPEE (100,150 and 200 mg/kg b.wt) or orlistat, for ten weeks. Liver tissue was homogenized and analyzed for lipid profiles, activities of superoxide dismutase (SOD), catalase (CAT) and malondialdehyde (MDA) content. Further, the expression levels of FAS and AMPK-1α were also studied in addition to histopathology examination of liver tissue in all the groups.

Results

HFD significantly increased hepatic liver total cholesterol (TC), triglycerides (TG), free fatty acids (FFA) and MDA but decreased the activities of SOD and CAT which were subsequently reversed by supplementation with TPEE in a dose-dependent manner. In addition, TPEE administration significantly down regulated hepatic mRNA expression of FAS but up regulated AMPK-1α compared to HFD alone fed group. Furthermore, western blot analysis of FAS has clearly demonstrated decreased expression of FAS in HFD + TPEE (200 mg/kg b.wt) treated group when compared to HFD group at protein level.

Conclusions

Our biochemical studies on hepatic lipid profiles and antioxidant enzyme activities supported by histological and expression studies suggest a potential therapeutic role for TPEE in regulating obesity through FAS.

Labisia pumila Upregulates Peroxisome Proliferator-Activated Receptor Gamma Expression in Rat Adipose Tissues and 3T3-L1 Adipocytes

Peroxisome proliferator-activated receptor gamma (PPARgamma) is a ligand-activated transcription factor that regulates lipid and glucose metabolism. We investigated the effects of Labisia pumila (LP) standardized water extract on PPARgamma transcriptional activity in adipocytes in vitro and in vivo. We used a rat model of dihydrotestosterone- (DHT-) induced polycystic ovary syndrome (PCOS), a condition characterized by insulin resistance. At 9 weeks of age, the PCOS rats were randomly subdivided into two groups: PCOS-LP (50 mg/kg/day of LP) and PCOS-control (1 mL of deionised water) for 4-5 weeks on the same schedule. Real-time RT-PCR was performed to determine the PPARgamma mRNA levels. LP upregulated PPARgamma mRNA level by 40% in the PCOS rats. Western blot analysis further demonstrated the increased PPARgamma protein levels in parallel with upregulation in mRNA. These observations were further proven by adipocytes culture. Differentiated 3T3-L1 adipocytes were treated with final concentration of 100  μ g/mL LP and compared to untreated control and 10  μ M of rosiglitazone (in type of thiazolidinediones). LP increased PPARgamma expressions at both mRNA and protein levels and enhanced the effect of glucose uptake in the insulin-resistant cells. The data suggest that LP may ameliorate insulin resistance in adipocytes via the upregulation of PPARgamma pathway.

Circadian clocks and metabolism

Circadian clocks maintain periodicity in internal cycles of behavior, physiology, and metabolism, enabling organisms to anticipate the 24-h rotation of the Earth. In mammals, circadian integration of metabolic systems optimizes energy harvesting and utilization across the light/dark cycle. Disruption of clock genes has recently been linked to sleep disorders and to the development of cardiometabolic disease. Conversely, aberrant nutrient signaling affects circadian rhythms of behavior. This chapter reviews the emerging relationship between the molecular clock and metabolic systems and examines evidence that circadian disruption exerts deleterious consequences on human health.

Functional comparison of chronological and in vitro aging: differential role of the cytoskeleton and mitochondria in mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are of high relevance for the regeneration of mesenchymal tissues such as bone and cartilage. The promising role of MSCs in cell-based therapies and tissue engineering appears to be limited due to a decline of their regenerative potential with increasing donor age, their limited availability in human tissues and the need of in vitro expansion prior to treatment. We therefore aimed to determine to which degree in vitro aging and chronological aging may be similar processes or if in vitro culture-related changes at the cellular and molecular level are at least altered as a function of donor age. For that purpose we established MSCs cultures from young (yMSCs) and aged (aMSCs) rats that were cultured for more than 100 passages. These long-term MSCs cultures were non-tumorigenic and exhibited similar surface marker patterns as primary MSCs of passage 2. During in vitro expansion, but not during chronological aging, MSCs progressively lose their progenitor characteristics, e.g., complete loss of osteogenic differentiation potential, diminished adipogenic differentiation, altered cell morphology and increased susceptibility towards senescence. Transcriptome analysis revealed that long-term in vitro MSCs cultivation leads to down-regulation of genes involved in cell differentiation, focal adhesion organization, cytoskeleton turnover and mitochondria function. Accordingly, functional analysis demonstrated altered mitochondrial morphology, decreased antioxidant capacities and elevated ROS levels in long-term cultivated yMSCs as well as aMSCs. Notably, only the MSC migration potential and their antioxidative capacity were altered by in vitro as well as chronological aging. Based on specific differences observed between the impact of chronological and in vitro MSC aging we conclude that both are distinct processes.

Hepatic FXR: key regulator of whole-body energy metabolism

The farnesoid X receptor (FXR) is a nuclear receptor whose activation leads to alterations in pathways involved in energy metabolism. For example, it serves as a bile acid receptor in tissues such as the liver, and as an energy metabolism regulator in liver, muscle and adipose tissue. However, the effects of FXR activation are not exclusive to the tissue where it is present, because receptor crosstalk affects tissues throughout the body. It has been demonstrated that FXR regulates the metabolism of not just bile acids, but also of fats and hydrocarbon metabolites. FXR is currently under study as a therapeutic target for the treatment of diseases of excess, such as diabetes. Here we review the effects of FXR activation in the response of an organism to excess energy.

Microarray Analysis of the Infrapatellar Fat Pad in Knee Osteoarthritis: Relationship with Joint Inflammation

Objective.

To examine differences in genes involved in fat metabolism, energy homeostasis, adipogenesis, and inflammation between endstage and early-stage knee osteoarthritis (OA) infrapatellar fat pads (IFP).

Methods.

Twenty-nine endstage and 5 early-stage primary OA IFP were harvested at knee surgery. Total RNA was extracted, labeled, and hybridized to whole-genome expression arrays. Unsupervised analysis of all samples using principal components analysis or 2-way hierarchical clustering showed groupings based on tissue source and disease. Statistical testing identified sets of genes that displayed differences between the 2 fat types. Western blot analysis was performed for protein expression of an identified gene of interest.

Results.

The 29 IFP demonstrated an elevation in the expression of adipokines such as adiponectin and leptin. A statistically significant increased expression was seen for genes of adipogenesis, such as peroxisome proliferator-activated receptor-γ (PPAR-γ), diacylglycerol acyltransferase 2 (DGAT2), cluster of differentiation (CD36), and thyroid hormone responsive spot (THRSP) in the severe OA fat pads as compared to the controls. A subset of 5 patients in the endstage OA group were consistently similar in gene expression to early OA tissue. Protein expression of PPAR-γ2 was 5.4-fold and PPAR-γ1 was 1.4-fold greater in endstage versus early OA tissue.

Conclusion.

Endstage OA fat pads demonstrated a significant upregulation of genes for fat metabolism and energy homeostasis and a mixed result for inflammatory cytokines.

A potential role of IL-6 in the chito-oligosaccharide-mediated inhibition of adipogenesis

Recent studies have suggested that chito-oligosaccharides can have anti-adipogenic properties. The objectives of the present study were to evaluate the anti-adipogenic potential of four different chito-oligosaccharides (molecular weight (MW) < 1000, 1000-3000, 3000-5000 and 5000-10,000 Da) and to identify molecular mechanisms underlying the chito-oligosaccharide-mediated inhibition of adipogenesis. Mouse 3T3-L1 cells were allowed to differentiate in the presence of chito-oligosaccharide. At day 8 post-induction of differentiation, lipid accumulation, free glycerol release and the quantitative expression of adipogenic marker genes were evaluated. Chito-oligosaccharides had concentration- and MW-dependent inhibitory effects on lipid accumulation (P < 0·001 and < 0·05, respectively), as well as a concentration-dependent effect (P < 0·001) on free glycerol release and the expression of adipogenic marker genes. The 5000-10,000 Da chito-oligosaccharide was selected for subsequent molecular studies. A panel of forty-four lipid metabolic pathway-specific genes was analysed by quantitative real-time PCR. Chito-oligosaccharide-mediated inhibition of adipogenesis was associated with the up-regulation of the IL-6 gene at all concentrations of chito-oligosaccharide examined and the PG-endoperoxide synthase 2 (PTGS2) gene at higher concentrations of chito-oligosaccharide. The effect of chito-oligosaccharide on gene expression was validated by measuring IL-6 protein concentrations in the media. Finally, an IL-6 promoter assay was developed to characterise the effect of chito-oligosaccharide on the transcriptional activity of the IL-6 promoter, which was increased in a concentration-dependent manner (P < 0·001). We conclude that IL-6 is a candidate signalling molecule in the chito-oligosaccharide-mediated inhibition of adipogenesis in 3T3-L1 cells.

Glucose-lowering effect of DLBS3233 is mediated through phosphorylation of tyrosine and upregulation of PPARγ and GLUT4 expression

Background:

DLBS3233 is a standardized extract combination containing Lagerstroemia speciosa and Cinnamomum burmannii. The effect of DLBS3233 on glucose uptake, adiponectin secretion, and insulin signaling was examined in this study.

Methods:

3T3 Swiss albino preadipocytes and adipocytes were used to investigate gene expression detected using the reverse transcription polymerase chain reaction method. Immunoblotting assay and in vitro glucose uptake assay were also carried out in the experiment.

Results:

DLBS3233 was seen to increase phosphorylation at the tyrosine residue of the insulin receptor substrate. DLBS3233 was also found to enhance the expression of genes associated with increased insulin signaling and sensitivity, such as peroxisome proliferator-activated receptor gamma, phosphatidylinositol-3 kinase, Akt, and glucose transporter 4. In addition, glucose transporter 4 protein levels were seen to increase as a result of DLBS3233 administration. The combination of extracts also increased glucose uptake and adiponectin secretion, and decreased resistin secretion significantly relative to control cells. Moreover, DLBS3233 administered to insulin-resistant Wistar rats showed an ability to control blood sugar, insulin levels, and other lipoproteins, including high-density lipoprotein, low-density lipoprotein, triglycerides, and total cholesterol.

Conclusion:

DLBS3233, as a combination of herbal extracts, holds promise in the treatment of type 2 diabetes, and possibly also in prevention of the disease.

Regulation of adipogenesis by nuclear receptor PPARγ is modulated by the histone demethylase JMJD2C

A potential strategy to combat obesity and its associated complications involves modifying gene expression in adipose cells to reduce lipid accumulation. The nuclear receptor Peroxisome Proliferator-activated receptor gamma (PPARγ) is the master regulator of adipose cell differentiation and its functional activation is currently used as a therapeutic approach for Diabetes Mellitus type 2. However, total activation of PPARγ induces undesirable secondary effects that might be set with a partial activation. A group of proteins that produce histone demethylation has been shown to modify the transcriptional activity of nuclear receptors. Here we describe the repressive action of the jumonji domain containing 2C/lysine demethylase 4 C (JMJD2C/KDM4C) on PPARγ transcriptional activation. JMJD2C significantly reduced the rosiglitazone stimulated PPARγ activation. This effect was mainly observed in experiments performed using the Tudor domains that may interact with histone deacetylase class 1 (HDAC) and this interaction probably reduces the mediated activation of PPARγ. Trichostatin A, a HDAC inhibitor, reduces the repressive effect of JMJD2C. When JMJD2C was over-expressed in 3T3-L1 cells, a reduction of differentiation was observed with the Tudor domain. In summary, we herein describe JMJD2C-mediated reduction of PPARgamma transcriptional activation as well as preadipocyte differentiation. This novel action of JMJD2C might have an important role in new therapeutic approaches to treat obesity and its complications.

Age and sex mediated changes in epicardial fat adipokines

Aging, which is an independent risk factor for heart disease, alters body fat mass and its function. Epicardial fat plays an important physiological and pathophysiological role on cardiac structure and function. This study investigated if aging altered the abundance of epicardial (EF) and abdominal fat (AF) derived mediators in a sex dependent manner in female and male Fischer 344×Brown Norway hybrid (FBN) rats. EF and AF were obtained from 48 female and male, young (6 months), aged (26/30 months) and very aged (30/36 months) FBN rats. Adipose derived anti-inflammatory and pro-inflammatory mediators were measured using ELISA, adipokine array and real-time qPCR. No dramatic changes in circulating lipids other than a higher triglyceride and high density lipoprotein in aged females and a significantly increased circulating adiponectin (p<0.005) in aged rats were observed. Real time PCR results showed that compared to 6 months old female rats, the aged (26 months) and very aged (30 months) rats had significantly lower levels of EF genes: adiponectin (p<0.005), PPARγ (p<0.01, 0.005), IL-6 (p<0.01) and PAI-1 (p<0.01, 0.01), respectively, but not in AF. In contrast, the male rats exhibited an increase in IL-6 in EF (p<0.005) but a decrease in adiponectin and PPARγ in AF with aging. These changes might be attributed to differences in adipocyte make-up or macrophage infiltration. In conclusion, aging had a more profound impact on EF derived mediators in female rather than male rats, which might help explain the increased risk to cardiovascular disease seen in older women.

PPAR-γ agonists and their effects on IGF-I receptor signaling: Implications for cancer

It is now well established that the development and progression of a variety of human malignancies are associated with dysregulated activity of the insulin-like growth factor (IGF) system. In this regard, promising drugs have been developed to target the IGF-I receptor or its ligands. These therapies are limited by the development of insulin resistance and compensatory hyperinsulinemia, which in turn, may stimulate cancer growth. Novel therapeutic approaches are, therefore, required. Synthetic PPAR-γ agonists, such as thiazolidinediones (TZDs), are drugs universally used as antidiabetic agents in patients with type 2 diabetes. In addition of acting as insulin sensitizers, PPAR-γ agonists mediate in vitro and in vivo pleiotropic anticancer effects. At least some of these effects appear to be linked with the downregulation of the IGF system, which is induced by the cross-talk of PPAR-γ agonists with multiple components of the IGF system signaling. As hyperinsulinemia is an emerging cancer risk factor, the insulin lowering action of PPAR-γ agonists may be expected to be also beneficial to reduce cancer development and/or progression. In light of these evidences, TZDs or other PPAR-γ agonists may be exploited in those tumors "addicted" to the IGF signaling and/or in tumors occurring in hyperinsulinemic patients.

Offspring from mothers fed a 'junk food' diet in pregnancy and lactation exhibit exacerbated adiposity that is more pronounced in females

We have shown previously that a maternal junk food diet during pregnancy and lactation plays a role in predisposing offspring to obesity. Here we show that rat offspring born to mothers fed the same junk food diet rich in fat, sugar and salt develop exacerbated adiposity accompanied by raised circulating glucose, insulin, triglyceride and/or cholesterol by the end of adolescence (10 weeks postpartum) compared with offspring also given free access to junk food from weaning but whose mothers were exclusively fed a balanced chow diet in pregnancy and lactation. Results also showed that offspring from mothers fed the junk food diet in pregnancy and lactation, and which were then switched to a balanced chow diet from weaning, exhibited increased perirenal fat pad mass relative to body weight and adipocyte hypertrophy compared with offspring which were never exposed to the junk food diet. This study shows that the increased adiposity was more enhanced in female than male offspring and gene expression analyses showed raised insulin-like growth factor-1 (IGF-1), insulin receptor substrate (IRS)-1, vascular endothelial growth factor (VEGF)-A, peroxisome proliferator-activated receptor-gamma (PPARgamma), leptin, adiponectin, adipsin, lipoprotein lipase (LPL), Glut 1, Glut 3, but not Glut 4 mRNA expression in females fed the junk food diet throughout the study compared with females never given access to junk food. Changes in gene expression were not as marked in male offspring with only IRS-1, VEGF-A, Glut 4 and LPL being up-regulated in those fed the junk food diet throughout the study compared with males never given access to junk food. This study therefore shows that a maternal junk food diet promotes adiposity in offspring and the earlier onset of hyperglycemia, hyperinsulinemia and/or hyperlipidemia. Male and female offspring also display a different metabolic, cellular and molecular response to junk-food-diet-induced adiposity.

Long-term hypoxia modulates expression of key genes regulating adipose function in the late-gestation ovine fetus

A major function of abdominal adipose in the newborn is nonshivering thermogenesis. Uncoupling protein (UCP) UCP1 and UCP2 play major roles in thermogenesis. The present study tested the hypothesis that long-term hypoxia (LTH) modulates expression of UCP1 and UCP2, and key genes regulating expression of these genes in the late-gestation ovine fetus. Ewes were maintained at high altitude (3,820 m) from 30 to 138 days gestation (dG); perirenal adipose tissue was collected from LTH and age-matched, normoxic control fetuses at 139-141 dG. Quantitative real-time PCR was used to analyze mRNA for UCP1, UCP2, 11beta hydroxysteroid dehydrogenase type 1 (HSD11B1) and 2 (HSD11B2), glucocorticoid receptor (GR), beta3 adrenergic receptor (beta3AR), deiodinase type 1 (DIO1) and DIO2, peroxisome proliferator activated receptor (PPAR) alpha and gamma and PPARgamma coactivator 1 (PGC1alpha). Concentrations of mRNA for UCP1, HSD11B1, PPARgamma, PGC1, DIO1, and DIO2 were significantly higher in perirenal adipose of LTH compared with control fetuses, while mRNA for HSD11B2, GR, or PPARalpha in perirenal adipose did not differ between control and LTH fetuses. The increased expression of UCP1 is likely an adaptive response to LTH, assuring adequate thermogenesis in the event of birth under oxygen-limiting conditions. Because both glucocorticoids and thyroid hormone regulate UCP1 expression, the increase in HSD11B1, DIO1, and DIO2 implicate increased adipose capacity for local synthesis of these hormones. PPARgamma and its coactivator may provide an underlying mechanism via which LTH alters development of the fetal adipocyte. These findings have important implications regarding fetal/neonatal adipose tissue function in response to LTH.

Different residues mediate recognition of 1-O-oleyllysophosphatidic acid and rosiglitazone in the ligand binding domain of peroxisome proliferator-activated receptor gamma

Here we showed that a naturally occurring ether analog of lysophosphatidic acid, 1-O-octadecenyl-2-hydroxy-sn-glycero-3-phosphate (AGP), is a high affinity partial agonist of the peroxisome proliferator-activated receptor gamma (PPARgamma). Binding studies using the PPARgamma ligand binding domain showed that [32P]AGP and [3H]rosiglitazone (Rosi) both specifically bind to PPARgamma and compete with each other. [32P]AGP bound PPARgamma with an affinity (Kdapp 60 nm) similar to that of Rosi. However, AGP displaced approximately 40% of bound [3H]Rosi even when applied at a 2000-fold excess. Activation of PPARgamma reporter gene expression by AGP and Rosi showed similar potency, yet AGP-mediated activation was approximately 40% that of Rosi. A complex between AGP and PPARgamma was generated using molecular modeling based on a PPARgamma crystal structure. AGP-interacting residues were compared with Rosi-interacting residues identified within the Rosi-PPARgamma co-crystal complex. These comparisons showed that the two ligands occupy partially overlapping positions but make different hydrogen bonding and ion pairing interactions. Site-specific mutants of PPARgamma were prepared to examine individual ligand binding. H323A and H449A mutants showed reduced binding of Rosi but maintained binding of AGP. In contrast, the R288A showed reduced AGP binding but maintained Rosi binding. Finally, alanine replacement of Tyr-473 abolished binding and activation by Rosi and AGP. These observations indicate that the endogenous lipid mediator AGP is a high affinity ligand of PPARgamma but that it binds via interactions distinct from those involved in Rosi binding. These distinct interactions are likely responsible for the partial PPARgamma agonism of AGP.