miR-669a-5p promotes adipogenic differentiation and induces browning in preadipocytes.

Obesity is a major global health issue that contributes to the occurrence of metabolic disorders. Based on this fact, understanding the underlying mechanisms and to uncover promising therapeutic approaches for obesity have attracted intense investigation. Brown adipose tissue (BAT) can help burns excess calories. Therefore, promoting White adipose tissue (WAT) browning and BAT activation is an attractive strategy for obesity treatment. MicroRNAs (miRNAs) are small, non-coding RNAs, which are involved in regulation of adipogenic processes and metabolic functions. Evidence is accumulating that miRNAs are important regulators for both brown adipocyte differentiation and white adipocyte browning. Here we report that the expression of miR-669a-5p increases during the adipogenic differentiation of 3T3-L1 and C3H10T1/2 adipocytes. miR-669a-5p supplementation promotes adipogenic differentiation and causes browning of 3T3-L1 and C3H10T1/2 cells. Moreover, the expression of miR-669a-5p is upregulated in iWAT of mice exposed to cold. These data demonstrate that miR-669a-5p plays a role in regulating adipocyte differentiation and fat browning.Abbreviations: Acadl: long-chain acyl-Coenzyme A dehydrogenase; Acadm: medium-chain acyl-Coenzyme A dehydrogenase; Acadvl: very long-chain acyl-Coenzyme A dehydrogenase, very long chain; Aco2: mitochondrial  aconitase 2; BAT: brown adipose tissue; Bmper: BMP-binding endothelial regulator; Cpt1-b:carnitine palmitoyltransferase 1b; Cpt2: carnitine palmitoyltransferase 2; Crat: carnitine acetyltransferase; Cs: citrate synthase; C2MC: Chromosome 2 miRNA cluster; DMEM: Dulbecco's modified Eagle medium; eWAT: epididymal white adipose tissue; ETC: electron transport chain; FAO: fatty acid oxidation; Fabp4:fatty acid binding protein 4; FBS: fetal bovine serum; Hadha: hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit alpha; Hadhb: hydroxyacyl-CoA dehydrogenase trifunctional multienzyme complex subunit beta; HFD: high fat diet; Idh3a: isocitrate dehydrogenase 3 alpha; iWAT: inguinal subcutaneous white adipose tissue; Lpl: lipoprotein lipase; Mdh2: malate dehydrogenase 2; NBCS: NewBorn Calf Serum; mt-Nd1: mitochondrial NADH dehydrogenase 1; Ndufb8:ubiquinone oxidoreductase subunit B8; Nrf1: nuclear respiratory factor 1; Pgc1α: peroxisome proliferative activated receptor gamma coactivator 1 alpha; Pgc1b: peroxisome proliferative activated receptor, gamma, coactivator 1 beta; Pparγ: peroxisome proliferator activated receptor gamma; Prdm16: PR domain containing 16; Rgs4: regulator of G-protein signaling 4; Sdhb: succinate dehydrogenase complex, subunit B; Sdhc: succinate dehydrogenase complex, subunit C; Sdhd: succinate dehydrogenase complex, subunit D; Sh3d21: SH3 domain containing 21; Sfmbt2: Scm-like with four mbt domains 2; TG: triglyceride; TCA: tricarboxylic acid cycle; Tfam: transcription factor A, mitochondrial; TMRE: tetramethylrhodamine, methyl ester; Ucp1: uncoupling protein 1; Uqcrc2: ubiquinol cytochrome c reductase core protein 2; WAT: White adipose tissue.

The natural compound rutaecarpine promotes white adipocyte browning through activation of the AMPK-PRDM16 axis.

The prevalence of obesity is increasing globally and is associated with many metabolic disorders, such as type 2 diabetes and cardiovascular diseases. In recent years, a number of studies suggest that promotion of white adipose browning represents a promising strategy to combat obesity and its related metabolic disorders. The aim of this study was to identify compounds that induce adipocyte browning and elucidate their mechanism of action. Among the 500 natural compounds screened, a small molecule named Rutaecarpine, was identified as a positive regulator of adipocyte browning both in vitro and in vivo. KEGG pathway analysis from RNA-seq data suggested that the AMPK signaling pathway was regulated by Rutaecarpine, which was validated by Western blot analysis. Furthermore, inhibition of AMPK signaling mitigated the browning effect of Rutaecaripine. The effect of Rutaecaripine on adipocyte browning was also abolished upon deletion of Prdm16, a downstream target of AMPK pathway. In collusion, Rutaecarpine is a potent chemical agent to induce adipocyte browning and may serve as a potential drug candidate to treat obesity.

Epigallocatechin gallate decreases plasma triglyceride, blood pressure, and serum kisspeptin in obese human subjects.

Obesity is one of major risk factors increasing chronic diseases including type II diabetes, cardiovascular diseases, and hypertension. The effects of epigallocatechin gallate (EGCG), the major active compound in green tea, on reduced obesity and improved metabolic profiles are still controversial. Furthermore, the effects of EGCG on human adipocyte lipolysis and browning of white adipocytes have not been elucidated. This study aimed to investigate the effects of EGCG on obesity, lipolysis, and browning of human white adipocytes. The results showed that, when compared to the baseline values, EGCG significantly decreased fasting plasma triglyceride levels (P < 0.05), systolic blood pressure (P < 0.05), diastolic blood pressure (P < 0.05), and serum kisspeptin levels (P < 0.05) after 8 weeks of supplement. On the other hand, supplement of EGCG in obese human subjects for 4 or 8 weeks did not decrease body weight, body mass index, waist and hip circumferences, nor total body fat mass or percentage when compared to their baseline values. The study in human adipocytes showed that EGCG did not increase the glycerol release when compared to vehicle, suggesting that it had no lipolytic effect. Furthermore, treatment of EGCG did not enhance uncoupling protein 1 (UCP1) mRNA expression in human white adipocytes when compared with treatment of pioglitazone, the peroxisome proliferator-activated receptor γ (PPAR-γ) agonist, suggesting that EGCG did not augment the browning effect of PPAR-γ on white adipocytes. This study revealed that EGCG reduced 2 metabolic risk factors which are triglyceride and blood pressure in the human experiment. We also showed a novel evidence that EGCG decreased kisspeptin levels. However, EGCG had no effects on obesity reduction in humans, lipolysis, nor browning of human white adipocytes.

The Rosmarinus Bioactive Compound Carnosic Acid Is a Novel PPAR Antagonist That Inhibits the Browning of White Adipocytes.

Thermogenic brown and brite adipocytes convert chemical energy from nutrients into heat. Therapeutics that regulate brown adipocyte recruitment and activity represent interesting strategies to control fat mass such as in obesity or cachexia. The peroxisome proliferator-activated receptor (PPAR) family plays key roles in the maintenance of adipose tissue and in the regulation of thermogenic activity. Activation of these receptors induce browning of white adipocyte. The purpose of this work was to characterize the role of carnosic acid (CA), a compound used in traditional medicine, in the control of brown/brite adipocyte formation and function. We used human multipotent adipose-derived stem (hMADS) cells differentiated into white or brite adipocytes. The expression of key marker genes was determined using RT-qPCR and western blotting. We show here that CA inhibits the browning of white adipocytes and favors decreased gene expression of thermogenic markers. CA treatment does not affect ß-adrenergic response. Importantly, the effects of CA are fully reversible. We used transactivation assays to show that CA has a PPARα/γ antagonistic action. Our data pinpoint CA as a drug able to control PPAR activity through an antagonistic effect. These observations shed some light on the development of natural PPAR antagonists and their potential effects on thermogenic response.

Vitamin D ameliorates adipose browning in chronic kidney disease cachexia.

Patients with chronic kidney disease (CKD) are often 25(OH)D3 and 1,25(OH)2D3 insufficient. We studied whether vitamin D repletion could correct aberrant adipose tissue and muscle metabolism in a mouse model of CKD-associated cachexia. Intraperitoneal administration of 25(OH)D3 and 1,25(OH)2D3 (75 µg/kg/day and 60 ng/kg/day respectively for 6 weeks) normalized serum concentrations of 25(OH)D3 and 1,25(OH)2D3 in CKD mice. Vitamin D repletion stimulated appetite, normalized weight gain, and improved fat and lean mass content in CKD mice. Vitamin D supplementation attenuated expression of key molecules involved in adipose tissue browning and ameliorated expression of thermogenic genes in adipose tissue and skeletal muscle in CKD mice. Furthermore, repletion of vitamin D improved skeletal muscle fiber size and in vivo muscle function, normalized muscle collagen content and attenuated muscle fat infiltration as well as pathogenetic molecular pathways related to muscle mass regulation in CKD mice. RNAseq analysis was performed on the gastrocnemius muscle. Ingenuity Pathway Analysis revealed that the top 12 differentially expressed genes in CKD were correlated with impaired muscle and neuron regeneration, enhanced muscle thermogenesis and fibrosis. Importantly, vitamin D repletion normalized the expression of those 12 genes in CKD mice. Vitamin D repletion may be an effective therapeutic strategy for adipose tissue browning and muscle wasting in CKD patients.

Huang-Qi San ameliorates hyperlipidemia with obesity rats via activating brown adipocytes and converting white adipocytes into brown-like adipocytes.

BACKGROUND: Brown adipose tissue (BAT) activation is a promising therapeutic target to treat hyperlipidemia with obesity. Huang-Qi San (HQS), an traditional Chinese medicine, can ameliorate hyperlipidemia with obesity, but its mechanism of action (MOA) is not understood. PURPOSE: To articulate the MOA for HQS with animal models. METHODS: The main chemical constituents of HQS were identified by high-performance liquid chromatography (HPLC) based assay. Hyperlipidemia with obesity rat models induced by high-fat diet were employed in the study. The levels of the fasting plasma glucose (FPG), triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C) and high-density lipoprotein-cholesterol (HDL-C) were measured to evaluate the ability of HQS to ameliorate hyperlipidemia with obesity. Pathological analyses of organs were conducted with Oil Red O staining, hematoxylin-eosin (H&E) staining and transmission electron microscopy. The expression of mRNAs related to thermogenic genes, fatty acid oxidation-related genes and mitochondria biogenic genes were examined by quantitative real-time PCR. The protein expressions of uncoupling protein 1 (UCP1) were investigated by immunohistochemistry and western blot. Simultaneously, the protein expression of PR domain containing 16 (PRDM16), ATP synthase F1 subunit alpha (ATP5A) was detected by western blot. RESULTS: HQS ameliorates metabolic disorder, lipid ectopic deposition, obesity and maintained glucose homeostasis in hyperlipidemia with obesity rats. HQS can significantly increase the number of mitochondria and reduced the size of the intracellular lipid droplets in BAT, and increase the expression of BAT activation-related genes (UCP1, PGC1α, PGC1ß, Prdm16, CD137, TBX1, CPT1a, PPARα, Tfam, NRF1 and NRF2) in vivo. Furthermore, UCP1, PRDM16 and ATP5A proteins of BAT were increased. CONCLUSION: HQS can activate BAT and browning of S-WAT (subcutaneous white adipose tissue) through activating the PRDM16/PGC1α/UCP1 pathway, augmenting mitochondrial biogenesis and fatty acid oxidation to increase thermogenesis and energy expenditure, resulting in a significant amelioration of hyperlipidemia with obesity. Therefore, HQS is an effective therapeutic medicine for the treatment of hyperlipidemia with obesity.

The Gintonin-Enriched Fraction of Ginseng Regulates Lipid Metabolism and Browning via the cAMP-Protein Kinase a Signaling Pathway in Mice White Adipocytes.

Obesity is a major health concern and is becoming an increasingly serious societal problem worldwide. The browning of white adipocytes has received considerable attention because of its potential protective effect against obesity-related metabolic disease. The gintonin-enriched fraction (GEF) is a non-saponin, glycolipoprotein component of ginseng that is known to have neuroprotective and anti-inflammatory effects. However, the anti-obesity and browning effects of GEF have not been explored to date. Therefore, we aimed to determine whether GEF has a preventive effect against obesity. We differentiated 3T3-L1 cells and mouse primary subcutaneous adipocytes for 8 days in the presence or absence of GEF, and then measured the expression of intermediates in signaling pathways that regulate triglyceride (TG) synthesis and browning by Western blotting and immunofluorescence analysis. We found that GEF reduced lipid accumulation by reducing the expression of pro-adipogenic and lipogenic factors, and increased lipolysis and thermogenesis, which may be mediated by an increase in the phosphorylation of protein kinase A. These findings suggest that GEF may induce fat metabolism and energy expenditure in white adipocytes and therefore may represent a potential treatment for obesity.

Anti-Adipogenic Effect of Neferine in 3T3-L1 Cells and Primary White Adipocytes.

Neferine, an alkaloid component extracted from lotus seed embryos, is known for its anti-inflammatory, anticancer, and antioxidant properties. However, the anti-adipogenic activity of neferine has not been thoroughly investigated. In this study, neferine was found to inhibit lipid accumulation in a dose-dependent manner during the differentiation of 3T3-L1 cells without inducing cytotoxicity. Real-time polymerase chain reaction and immunoblot analysis revealed the downregulation in the expression of peroxisome proliferator activated receptor gamma (PPARγ), CCAAT/enhancer-binding protein alpha (C/EBPα), sterol regulatory element-binding protein-1c (SREBP-1c), and fatty acid synthase (FAS) and the upregulation in carnitine palmitoyltransferase-1 (CPT-1) and sirtuin 1 (SIRT1) levels following neferine treatment. Furthermore, neferine increased the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC), which is an important regulator of fatty acid oxidation. Our result indicates that neferine attenuates adipogenesis and promotes lipid metabolism by activating AMPK-mediated signaling. Therefore, neferine may serve as a therapeutic candidate for obesity treatment.

Urolithin A exerts antiobesity effects through enhancing adipose tissue thermogenesis in mice.

Obesity leads to multiple health problems, including diabetes, fatty liver, and even cancer. Here, we report that urolithin A (UA), a gut-microflora-derived metabolite of pomegranate ellagitannins (ETs), prevents diet-induced obesity and metabolic dysfunctions in mice without causing adverse effects. UA treatment increases energy expenditure (EE) by enhancing thermogenesis in brown adipose tissue (BAT) and inducing browning of white adipose tissue (WAT). Mechanistically, UA-mediated increased thermogenesis is caused by an elevation of triiodothyronine (T3) levels in BAT and inguinal fat depots. This is also confirmed in UA-treated white and brown adipocytes. Consistent with this mechanism, UA loses its beneficial effects on activation of BAT, browning of white fat, body weight control, and glucose homeostasis when thyroid hormone (TH) production is blocked by its inhibitor, propylthiouracil (PTU). Conversely, administration of exogenous tetraiodothyronine (T4) to PTU-treated mice restores UA-induced activation of BAT and browning of white fat and its preventive role on high-fat diet (HFD)-induced weight gain. Together, these results suggest that UA is a potent antiobesity agent with potential for human clinical applications.

Ginsenoside Rg3 Induces Browning of 3T3-L1 Adipocytes by Activating AMPK Signaling.

Ginsenoside Rg3, one of the major components in Panax ginseng, has been reported to possess several therapeutic effects including anti-obesity properties. However, its effect on the browning of mature white adipocytes as well as the underlying mechanism remains poorly understood. In this study, we suggested a novel role of Rg3 in the browning of mature 3T3-L1 adipocytes by upregulating browning-related gene expression. The browning effects of Rg3 on differentiated 3T3-L1 adipocytes were evaluated by analyzing browning-related markers using quantitative PCR, immunoblotting, and immunostaining. In addition, the size and sum area of lipid droplets in differentiated 3T3-L1 adipocytes were measured using Oil-Red-O staining. In mature 3T3-L1 adipocytes, Rg3 dose-dependently induced the expression of browning-related genes such as Ucp1, Prdm16, Pgc1α, Cidea, and Dio2. Moreover, Rg3 induced the expression of beige fat-specific genes (CD137 and TMEM26) and lipid metabolism-associated genes (FASN, SREBP1, and MCAD), which indicated the activation of lipid metabolism by Rg3. We also demonstrated that activation of 5' adenosine monophosphate-activated protein kinase (AMPK) is required for Rg3-mediated up-regulation of browning gene expression. Moreover, Rg3 inhibited the accumulation of lipid droplets and reduced the droplet size in mature 3T3-L1 adipocytes. Taken together, this study identifies a novel role of Rg3 in browning of white adipocytes, as well as suggesting a potential mechanism of an anti-obesity effect of Panax ginseng.

Regulation of thermogenic capacity in brown and white adipocytes by the prebiotic high-esterified pectin and its postbiotic acetate.

OBJECTIVES: High-esterified pectin (HEP) is a prebiotic able to modulate gut microbiota, associated with health-promoting metabolic effects in glucose and lipid metabolism and adipostatic hormone sensitivity. Possible effects regulating adaptive thermogenesis and energy waste are poorly known. Therefore, we aimed to study how physiological supplementation with HEP is able to affect microbiota, energy metabolism and adaptive thermogenic capacity, and to contribute to the healthier phenotype promoted by HEP supplementation, as previously shown. We also attempted to decipher some of the mechanisms involved in the HEP effects, including in vitro experiments. SUBJECTS AND EXPERIMENTAL DESIGN: We used a model of metabolic malprogramming consisting of the progeny of rats with mild calorie restriction during pregnancy, both under control diet and an obesogenic (high-sucrose) diet, supplemented with HEP, combined with in vitro experiments in primary cultured brown and white adipocytes treated with the postbiotic acetate. RESULTS: Our main findings suggest that chronic HEP supplementation induces markers of brown and white adipose tissue thermogenic capacity, accompanied by a decrease in energy efficiency, and prevention of weight gain under an obesogenic diet. We also show that HEP promotes an increase in beneficial bacteria in the gut and peripheral levels of acetate. Moreover, in vitro acetate can improve adipokine production, and increase thermogenic capacity and browning in brown and white adipocytes, respectively, which could be part of the protection mechanism against excess weight gain observed in vivo. CONCLUSION: HEP and acetate stand out as prebiotic/postbiotic active compounds able to modulate both brown-adipocyte metabolism and browning and protect against obesity.

Black Ginseng and Ginsenoside Rb1 Promote Browning by Inducing UCP1 Expression in 3T3-L1 and Primary White Adipocytes.

In this study, we investigated the effects of black ginseng (BG) and ginsenoside Rb1, which induced browning effects in 3T3-L1 and primary white adipocytes (PWATs) isolated from C57BL/6 mice. BG and Rb1 suppressed the expressions of CCAAT/enhancer-binding protein alpha (C/EBPα) and sterol regulatory element-binding transcription factor-1c (SREBP-1c), whereas the expression level of peroxisome proliferator-activated receptor gamma (PPARγ) was increased. Furthermore, BG and Rb1 enhanced the protein expressions of the brown-adipocyte-specific markers PR domain containing 16 (PRDM16), peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and uncoupling protein 1 (UCP1). These results were further supported by immunofluorescence images of mitochondrial biogenesis. In addition, BG and Rb1 induced expressions of brown-adipocyte-specific marker proteins by AMP-activated protein kinase (AMPK) activation. BG and Rb1 exert antiobesity effects by inducing browning in 3T3-L1 cells and PWATs through AMPK-mediated pathway activation. We suggest that BG and Rb1 act as potential functional antiobesity food agents.

Black Raspberry (Rubus coreanus Miquel) Promotes Browning of Preadipocytes and Inguinal White Adipose Tissue in Cold-Induced Mice.

The alteration of white adipose tissue (WAT) "browning", a change of white into beige fat, has been considered as a new therapeutic strategy to treat obesity. In this study, we investigated the browning effect of black raspberry (Rubus coreanus Miquel) using in vitro and in vivo models. Black raspberry water extract (BRWE) treatment inhibited lipid accumulation in human mesenchymal stem cells (hMSCs) and zebrafish. To evaluate the thermogenic activity, BRWE was orally administered for 2 weeks, and then, the mice were placed in a 4 °C environment. As a result, BRWE treatment increased rectal temperature and inguinal WAT (iWAT) thermogenesis by inducing the expression of beige fat specific markers such as PR domain zinc-finger protein 16 (PRDM16), uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), and t-box protein 1 (TBX1) in cold-exposed mice. Furthermore, ellagic acid (EA), a constituent of BRWE, markedly promoted beige specific markers: UCP1, PGC1α, TBX1, and nuclear respiratory factor 1 in beige differentiation media (DM)-induced 3T3-L1 adipocytes. Our findings indicate that BRWE can promote beige differentiation/activation, and EA is the active compound responsible for such effect. Thus, we suggest the nature-derived agents BRWE and EA as potential agents for obesity treatment.

Preadipocytes of obese humans display gender-specific bioenergetic responses to glucose and insulin.

BACKGROUND/OBJECTIVES: Although the prevalence of obesity and its associated metabolic disorders is increasing in both sexes, the clinical phenotype differs between men and women, highlighting the need for individual treatment options. Mitochondrial dysfunction in various tissues, including white adipose tissue (WAT), has been accepted as a key factor for obesity-associated comorbidities such as diabetes. Given higher expression of mitochondria-related genes in the WAT of women, we hypothesized that gender differences in the bioenergetic profile of white (pre-) adipocytes from obese (age- and BMI-matched) donors must exist. SUBJECTS/METHODS: Using Seahorse technology, we measured oxygen consumption rates (OCR) and extracellular acidification rates (ECAR) of (pre-)adipocytes from male (n = 10) and female (n = 10) deeply-phenotyped obese donors under hypo-, normo- and hyperglycemic (0, 5 and 25 mM glucose) and insulin-stimulated conditions. Additionally, expression levels (mRNA/protein) of mitochondria-related genes (e.g. UQCRC2) and glycolytic enzymes (e.g. PKM2) were determined. RESULTS: Dissecting cellular OCR and ECAR into different functional modules revealed that preadipocytes from female donors show significantly higher mitochondrial to glycolytic activity (higher OCR/ECAR ratio, p = 0.036), which is supported by a higher ratio of UQCRC2 to PKM2 mRNA levels (p = 0.021). However, no major gender differences are detectable in in vitro differentiated adipocytes (e.g. OCR/ECAR, p = 0.248). Importantly, glucose and insulin suppress mitochondrial activity (i.e. ATP-linked respiration) significantly only in preadipocytes of female donors, reflecting their trends towards higher insulin sensitivity. CONCLUSIONS: Collectively, we show that preadipocytes, but not in vitro differentiated adipocytes, represent a model system to reveal gender differences with clinical importance for metabolic disease status. In particular preadipocytes of females maintain enhanced mitochondrial flexibility, as demonstrated by pronounced responses of ATP-linked respiration to glucose.

9-PAHSA promotes browning of white fat via activating G-protein-coupled receptor 120 and inhibiting lipopolysaccharide / NF-kappa B pathway.

Browning of white adipose tissue is a novel mechanism to counteract obesity in view of its thermogenic activity. Activation of G-protein-coupled receptor 120 (GPR120) can promote the browning of white fat. 9-PAHSA, an endogenous mammalian lipid, which is acting as the ligand of GPR120 to enhance glucose uptake and exert anti-inflammatory effect. In the study, we would like to investigate the biological effects of 9-PAHSA on adipocyte browning. Here, we show that 9-PAHSA induces browning of 3T3-L1 adipocytes via enhanced expression of brown fat specific genes. 9-PAHSA-induced browning in white adipocytes of WT mice and ob/ob mice was investigated by determining expression levels of brown adipocyte-specific genes/proteins by quantitative real-time polymerase chain reaction analysis, immunoblot analysis and immunochemical staining. The effects of 9-PAHSA on brown fat markers in 3T3-L1 cells were decreased when GPR120 gene was silenced. To investigate the molecular mechanism of 9-PAHSA on adipocyte browning, lipopolysaccharide (LPS)-induced inflammatory model was conducted. 9-PAHSA treatment abolished LPS-induced NF-kappa B (NF-κB) activation and inflammatory cytokine secretion. But these anti-inflammatory effects of 9-PAHSA were attenuated by GPR120 knockdown. Our finding demonstrated that the browning of adipocyte was induced by 9-PAHSA through activating GPR120 and inhibiting the LPS/NF-κB pathway. This promising result will help to reveal the potential pathogenesis of obesity.

Effects of Genistein on Differentiation and Viability of Human Visceral Adipocytes.

Obesity can lead to pathological growth of adipocytes by inducing inflammation and oxidative stress. Genistein could be a potential candidate for the treatment of obesity due to its antioxidant properties. Specific kits were used to examine the effects of genistein vs adiponectin on human visceral pre-adipocytes differentiation, cell viability, mitochondrial membrane potential, and oxidative stress in pre-adipocytes and in white/brown adipocytes. Western Blot was performed to examine changes in protein activation/expression. Genistein increased human visceral pre-adipocytes differentiation and browning, and caused a dose-related improvement of cell viability and mitochondrial membrane potential. Similar effects were observed in brown adipocytes and in white adipocytes, although in white cells the increase of cell viability was inversely related to the dose. Moreover, genistein potentiated AMP-activated protein kinase (AMPK)/mitofusin2 activation/expression in pre-adipocytes and white/brown adipocytes and protected them from the effects of hydrogen peroxide. The effects caused by genistein were similar to those of adiponectin. The results obtained showed that genistein increases human visceral pre-adipocytes differentiation and browning, protected against oxidative stress in pre-adipocytes and white/brown adipocytes through mechanisms related to AMPK-signalling and the keeping of mitochondrial function.

Proteomic profiling of Ganoderma tsugae ethanol extract-induced adipogenesis displaying browning features.

Ganoderma is classified as a top grade traditional Chinese medicine for promoting human health by regulating 'vital energy'. Its potency towards metabolism and energy homeostasis, particularly, metabolic adaptations of adipocytes, needs to be re-evaluated through an evidence-based study. Here, the triterpenoid-rich Ganoderma tsugae ethanol extract (GTEE) was found to contribute towards adipogenesis accompanied with elevated intracellular lipid metabolic flux. Additionally, proteomic profiling revealed GTEE-upregulated mitochondrial remodeling and chemical energy redox modifications, which display UCP1-positive browning fat-selective features and a NADH-mediated adaptive mechanism. GTEE-treated mice with diet-induced obesity also resulted in the amelioration of white adipocyte hypertrophy and the appearance of UCP1-positive browning adipocytes. Our novel findings unravel that GTEE could promote intracellular metabolic flexibility and plasticity followed by the induction of adipocyte browning.

Aegeline inspired synthesis of novel ß3-AR agonist improves insulin sensitivity in vitro and in vivo models of insulin resistance.

BACKGROUND AND PURPOSE: In our drug discovery program of natural product, earlier we have reported Aegeline that is N-acylated-1-amino-2- alcohol, which was isolated from the leaves of Aeglemarmelos showed anti-hyperlipidemic activity for which the QSAR studies predicted the compound to be the ß3-AR agonist, but the mechanism of its action was not elucidated. In our present study, we have evaluated the ß3-AR activity of novel N-acyl-1-amino-3-arylopropanol synthetic mimics of aegeline and its beneficial effect in insulin resistance. In this study, we have proposed the novel pharmacophore model using reported molecules for antihyperlipidemic activity. The reported pharmacophore features were also compared with the newly developed pharmacophore model for the observed biological activity. EXPERIMENTAL APPROACH: Based on 3D pharmacophore modeling of known ß3AR agonist, we screened 20 synthetic derivatives of Aegeline from the literature. From these, the top scoring compound 10C was used for further studies. The in-slico result was further validated in HEK293T cells co-trransfected with human ß3-AR and CRE-Luciferase reporter plasmid for ß3-AR activity.The most active compound was selected and ß3-AR activity was further validated in white and brown adipocytes differentiated from human mesenchymal stem cells (hMSCs). Insulin resistance model developed in hMSC derived adipocytes was used to study the insulin sensitizing property. 8 week HFD fed C57BL6 mice was given 50 mg/Kg of the selected compound and metabolic phenotyping was done to evaluate its anti-diabetic effect. RESULTS: As predicted by in-silico 3D pharmacophore modeling, the compound 10C was found to be the most active and specific ß3-AR agonist with EC50 value of 447 nM. The compound 10C activated ß3AR pathway, induced lipolysis, fatty acid oxidation and increased oxygen consumption rate (OCR) in human adipocytes. Compound 10C induced expression of brown adipocytes specific markers and reverted chronic insulin induced insulin resistance in white adipocytes. The compound 10C also improved insulin sensitivity and glucose tolerance in 8 week HFD fed C57BL6 mice. CONCLUSION: This study enlightens the use of in vitro insulin resistance model close to human physiology to elucidates the insulin sensitizing activity of the compound 10C and edifies the use of ß3AR agonist as therapeutic interventions for insulin resistance and type 2 diabetes.

Betaine Supplementation Enhances Lipid Metabolism and Improves Insulin Resistance in Mice Fed a High-Fat Diet.

Obesity is a major driver of metabolic diseases such as nonalcoholic fatty liver disease, certain cancers, and insulin resistance. However, there are no effective drugs to treat obesity. Betaine is a nontoxic, chemically stable and naturally occurring molecule. This study shows that dietary betaine supplementation significantly inhibits the white fat production in a high-fat diet (HFD)-induced obese mice. This might be due to betaine preventing the formation of new white fat (WAT), and guiding the original WAT to burn through stimulated mitochondrial biogenesis and promoting browning of WAT. Furthermore, dietary betaine supplementation decreases intramyocellular lipid accumulation in HFD-induced obese mice. Further analysis shows that betaine supplementation reduced intramyocellular lipid accumulation might be associated with increasing polyunsaturated fatty acids (PUFA), fatty acid oxidation, and the inhibition of fatty acid synthesis in muscle. Notably, by performing insulin-tolerance tests (ITTs) and glucose-tolerance tests (GTTs), dietary betaine supplementation could be observed for improvement of obesity and non-obesity induced insulin resistance. Together, these findings could suggest that inhibiting WAT production, intramyocellular lipid accumulation and inflammation, betaine supplementation limits HFD-induced obesity and improves insulin resistance.

Lack of effects of myo-inositol on metabolism of primary rat adipocytes.

Myo-inositol is a ubiquitous cyclitol, has an important regulatory role, and its intracellular depletion is associated with pathological changes. Effects of myo-inositol on adipose tissue are poorly elucidated. In this report, short-term influence of 20, 100, and 500 µM myo-inositol on metabolism of the isolated rat adipocytes was studied. Cells were incubated for 90 min with glucose and insulin with or without myo-inositol and glucose conversion to lipids and lactate release were measured. Moreover, effects of myo-inositol on lipolysis and on the antilipolytic action of insulin were also studied. It was demonstrated that lipogenesis and lactate release were unchanged by myo-inositol. Moreover, lipolytic response to epinephrine and dibutyryl-cAMP was also unchanged. Myo-inositol was also found to be without influence on the antilipolytic action of insulin. Results of this study show that metabolism of the isolated rat adipocytes is not affected by short-term exposure of these cells to myo-inositol.