Inhibition of the RPS6KA1/FoxO1 signaling axis by hydroxycitric acid attenuates HFD-induced obesity through MCE suppression.

BACKGROUND: Because obesity is associated with a hyperplasia-mediated increase in adipose tissue, inhibiting cell proliferation during mitotic clonal expansion (MCE) is a leading strategy for preventing obesity. Although (-)-hydroxycitric acid (HCA) is used to control obesity, the molecular mechanisms underlying its effects on MCE are poorly understood. PURPOSE: This study aimed to investigate the potential effects of HCA on MCE and underlying molecular mechanisms affecting adipogenesis and obesity improvements. METHODS: Preadipocyte cell line, 3T3-L1, were treated with HCA; oil red O, cell proliferation, cell cycle, and related alterations in signaling pathways were examined. High-fat diet (HFD)-fed mice were administered HCA for 12 weeks; body and adipose tissues weights were evaluated, and the regulation of signaling pathways in epidydimal white adipose tissue were examined in vivo. RESULTS: Here, we report that during MCE, HCA attenuates the proliferation of the preadipocyte cell line, 3T3-L1, by arresting the cell cycle at the G0/G1 phase. In addition, HCA markedly inhibits Forkhead Box O1 (FoxO1) phosphorylation, thereby inducing the expression of cyclin-dependent kinase inhibitor 1B and suppressing the levels of cyclin-dependent kinase 2, cyclin E1, proliferating cell nuclear antigen, and phosphorylated retinoblastoma. Importantly, we found that ribosomal protein S6 kinase A1 (RPS6KA1) influences HCA-mediated inactivation of FoxO1 and its nuclear exclusion. An animal model of obesity revealed that HCA reduced high-fat diet-induced obesity by suppressing adipocyte numbers as well as epididymal and mesenteric white adipose tissue mass, which is attributed to the regulation of RPS6KA1, FoxO1, CDKN1B and PCNA that had been consistently identified in vitro. CONCLUSIONS: These findings provide novel insights into the mechanism by which HCA regulates adipogenesis and highlight the RPS6KA1/FoxO1 signaling axis as a therapeutic target for obesity.

Mulberry and Hippophae-based solid beverage promotes weight loss in rats by antagonizing white adipose tissue PPARγ and FGFR1 signaling.

Obesity, a multifactorial disease with many complications, has become a global epidemic. Weight management, including dietary supplementation, has been confirmed to provide relevant health benefits. However, experimental evidence and mechanistic elucidation of dietary supplements in this regard are limited. Here, the weight loss efficacy of MHP, a commercial solid beverage consisting of mulberry leaf aqueous extract and Hippophae protein peptides, was evaluated in a high-fat high-fructose (HFF) diet-induced rat model of obesity. Body component analysis and histopathologic examination confirmed that MHP was effective to facilitate weight loss and adiposity decrease. Pathway enrichment analysis with differential metabolites generated by serum metabolomic profiling suggests that PPAR signal pathway was significantly altered when the rats were challenged by HFF diet but it was rectified after MHP intervention. RNA-Seq based transcriptome data also indicates that MHP intervention rectified the alterations of white adipose tissue mRNA expressions in HFF-induced obese rats. Integrated omics reveals that the efficacy of MHP against obesogenic adipogenesis was potentially associated with its regulation of PPARγ and FGFR1 signaling pathway. Collectively, our findings suggest that MHP could improve obesity, providing an insight into the use of MHP in body weight management.

Guanidinoacetic acid ameliorates hepatic steatosis and inflammation and promotes white adipose tissue browning in middle-aged mice with high-fat-diet-induced obesity.

Guanidinoacetic acid (GAA) is a naturally occurring amino acid derivative that plays a critical role in energy metabolism. In recent years, a growing body of evidence has emerged supporting the importance of GAA in metabolic dysfunction. Hence, we aimed to investigate the effects of GAA on hepatic and adipose tissue metabolism, as well as systemic inflammatory responses in obese middle-aged mice models and attempted to explore the underlying mechanism. We found that dietary supplementation of GAA inhibited inguinal white adipose tissue (iWAT) hypertrophy in high-fat diet (HFD)-fed mice. In addition, GAA supplementation observably decreased the levels of some systemic inflammatory factors, including IL-4, TNF-α, IL-1ß, and IL-6. Intriguingly, GAA supplementation ameliorated hepatic steatosis and lipid deposition in HFD-fed mice, which was revealed by decreased levels of TG, TC, LDL-C, PPARγ, SREBP-1c, FASN, ACC, FABP1, and APOB and increased levels of HDL-C in the liver. Moreover, GAA supplementation increased the expression of browning markers and mitochondrial-related genes in the iWAT. Further investigation showed that dietary GAA promoted the browning of the iWAT via activating the AMPK/Sirt1 signaling pathway and might be associated with futile creatine cycling in obese mice. These results indicate that GAA has the potential to be used as an effective ingredient in dietary interventions and thus may play an important role in ameliorating and preventing HFD-induced obesity and related metabolic diseases.

Hyperbaric oxygen therapy promotes the browning of white fat and contributes to the healing of diabetic wounds.

Non-healing wounds are one of the chronic complications of diabetes and have remained a worldwide challenge as one of the major health problems. Hyperbaric oxygen (HBO) therapy is proven to be very successful for diabetic wound treatment, for which the molecular basis is not understood. Adipocytes regulate multiple aspects of repair and may be therapeutic for inflammatory diseases and defective wound healing associated with aging and diabetes. Endothelial cell-derived extracellular vesicles could promote wound healing in diabetes. To study the mechanism by which HBO promotes wound healing in diabetes, we investigated the effect of HBO on fat cells in diabetic mice. A diabetic wound mouse model was established and treated with HBO. Haematoxylin and eosin (H&E) staining and immunofluorescence were used for the analysis of wound healing. To further explore the mechanism, we performed whole-genome sequencing on extracellular vesicles (EVs). Furthermore, we conducted in vitro experiments. Specifically, exosomes were collected from human umbilical vein endothelial cell (HUVEC) cells after HBO treatment, and then these exosomes were co-incubated with adipose tissue. The wound healing rate in diabetic mice treated with HBO was significantly higher. HBO therapy promotes the proliferation of adipose precursor cells. HUVEC-derived exosomes treated with HBO significantly promoted fat cell browning. These data clarify that HBO therapy may promote vascular endothelial cell proliferation and migration, and promote browning of fat cells through vascular endothelial cells derived exosomes, thereby promoting diabetic wound healing. This provides new ideas for the application of HBO therapy in the treatment of diabetic trauma.

trans-Palmitoleic acid promotes adipose thermogenesis to reduce obesity via hypothalamic FFAR1 signaling.

Diet-induced thermogenesis (DIT) is crucial for maintaining body weight homeostasis, and the role of dietary fatty acids in modulating DIT is essential. However, the underlying mechanism of fatty acid regulated diet-induced thermogenesis remains elusive. Utilizing the diet- and genetic ablation-induced obese mice models, we found that the C16 unsaturated fatty acids, trans-palmitoleic acid (TPA) and cis-palmitoleic acid (CPA), significantly increased the energy expenditure by promoting the thermogenesis of brown adipose tissues and the production of beige cells in white adipose. As a result, there is a significant reduction in the occurrence of obesity, associated hepatic steatosis and hyperglycemia. Notably, TPA exhibited more potent effects on promoting DIT and alleviating obesity than CPA did. Using inhibitor and gene deletion mice models, we unveiled that TPA acted as a signaling molecule to play a biological function, which could be sensed by the hypothalamic FFAR1 to activate the sympathetic nervous system in promoting adipose tissue thermogenesis. Together, these results demonstrate the underlying mechanism of free fatty acids associated-DIT and will provide fresh insights into the roles of trans-fatty acids in the development of obesity.

Melatonin supplementation in obese mothers reduces hypothalamic inflammation and enhances thermogenesis in mice progeny.

Maternal obesity might induce obesity and metabolic alterations in the progeny. The study aimed to determine the effect of supplementing obese mothers with Mel (Mel) on thermogenesis and inflammation. C57BL/6 female mice (mothers) were fed from weaning to 12 weeks control diet (C, 17% kJ as fat) or a high-fat diet (HF, 49% kJ as fat) and then matted with male mice fed the control diet. Melatonin (10 mg/kg daily) was supplemented to mothers during gestation and lactation, forming the groups C, CMel, HF, and HFMel (n = 10/group). Twelve-week male offspring were studied (plasma biochemistry, immunohistochemistry, protein, and gene expressions at the hypothalamus - Hyp, subcutaneous white adipose tissue - sWAT, and interscapular brown adipose tissue - iBAT). Comparing HFMel vs. HF offspring, fat deposits and plasmatic proinflammatory markers decreased. Also, HFMel showed decreased Hyp proinflammatory markers and neuropeptide Y (anabolic) expression but improved proopiomelanocortin (catabolic) expression. Besides, HFMel sWAT adipocytes changed to a beige phenotype with-beta-3 adrenergic receptor and uncoupling protein-1 activation, concomitant with browning genes activation, triggering the iBAT thermogenic activity. In conclusion, compelling evidence indicated the beneficial effects of supplementing obese mothers with Mel on the health of their mature male offspring. Mel led to sWAT browning-related gene enhancement, increased iBAT thermogenis, and mitigated hypothalamic inflammation. Also, principal component analysis of the data significantly separated the untreated obese mother progeny from the progeny of treated obese mothers. If confirmed in humans, the findings encourage a future guideline recommending Mel supplementation during pregnancy and breastfeeding.

Alisol B 23-acetate promotes white adipose tissue browning to mitigate high-fat diet-induced obesity by regulating mTOR-SREBP1 signaling.

OBJECTIVE: Obesity is a global health concern with management strategies encompassing bariatric surgery and anti-obesity drugs; however, concerns regarding complexities and side effects persist, driving research for more effective, low-risk strategies. The promotion of white adipose tissue (WAT) browning has emerged as a promising approach. Moreover, alisol B 23-acetate (AB23A) has demonstrated efficacy in addressing metabolic disorders, suggesting its potential as a therapeutic agent in obesity management. Therefore, in this study, we aimed to investigate the therapeutic potential of AB23A for mitigating obesity by regulating metabolic phenotypes and lipid distribution in mice fed a high-fat diet (HFD). METHODS: An obesity mouse model was established by administration of an HFD. Glucose and insulin metabolism were assessed via glucose and insulin tolerance tests. Adipocyte size was determined using hematoxylin and eosin staining. The expression of browning markers in WAT was evaluated using Western blotting and quantitative real-time polymerase chain reaction. Metabolic cage monitoring involved the assessment of various parameters, including food and water intake, energy metabolism, respiratory exchange rates, and physical activity. Moreover, oil red O staining was used to evaluate intracellular lipid accumulation. A bioinformatic analysis tool for identifying the molecular mechanisms of traditional Chinese medicine was used to examine AB23A targets and associated signaling pathways. RESULTS: AB23A administration significantly reduced the weight of obese mice, decreased the mass of inguinal WAT, epididymal WAT, and perirenal adipose tissue, improved glucose and insulin metabolism, and reduced adipocyte size. Moreover, treatment with AB23A promoted the expression of browning markers in WAT, enhanced overall energy metabolism in mice, and had no discernible effect on food intake, water consumption, or physical activity. In 3T3-L1 cells, AB23A inhibited lipid accumulation, and both AB23A and rapamycin inhibited the mammalian target of rapamycin-sterol regulatory element-binding protein-1 (mTOR-SREBP1) signaling pathway. Furthermore, 3-isobutyl-1-methylxanthine, dexamethasone and insulin, at concentrations of 0.25 mmol/L, 0.25 µmol/L and 1 µg/mL, respectively, induced activation of the mTOR-SREBP1 signaling pathway, which was further strengthened by an mTOR activator MHY1485. Notably, MHY1485 reversed the beneficial effects of AB23A in 3T3-L1 cells. CONCLUSION: AB23A promoted WAT browning by inhibiting the mTOR-SREBP1 signaling pathway, offering a potential strategy to prevent obesity. Please cite this article as: Han LL, Zhang X, Zhang H, Li T, Zhao YC, Tian MH, Sun FL, Feng B. Alisol B 23-acetate promotes white adipose tissue browning to mitigate high-fat diet-induced obesity by regulating mTOR-SREBP1 signaling. J Integr Med. 2024; 22(1): 83-92.

Flavonoid extracts of Citrus aurantium L. var. amara Engl. Promote browning of white adipose tissue in high-fat diet-induced mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Obesity has become a public burden worldwide due to its booming incidence and various complications, and browning of white adipose tissue (WAT) is recognized as a hopeful strategy to combat it. Blossom of Citrus aurantium L. var. amara Engl. (CAVA) is a popular folk medicine and dietary supplement used for relieving dyspepsia, which is recorded in the Chinese Materia Medica. Our previous study showed that blossom of CAVA had anti-obesity potential, while its role in browning of WAT was still unclear. AIM OF THE STUDY: This study aimed to characterize the constituents in flavonoids from blossom of CAVA (CAVAF) and to clarify the anti-obesity capacities especially the effects on browning of WAT. MATERIALS AND METHODS: Gradient ethanol eluents from blossom of CAVA were obtained by AB-8 macroporous resin. 3T3-L1 cells and pancreatic lipase inhibition assay were employed to investigate the potential anti-obesity effects in vitro. HPLC and UPLC/MS assays were performed to characterize the chemical profiles of different eluents. Network pharmacology and molecular docking assays were used to reveal potential anti-obesity targets. Furthermore, high-fat diet (HFD)-induced mice were constructed to explore the anti-obesity actions and mechanisms in vivo. RESULTS: 30% ethanol eluents with high flavonoid content and great inhibition on proliferation of 3T3-L1 preadipocytes and pancreatic lipase activity were regarded as CAVAF. 19 compounds were identified in CAVAF. Network pharmacology analysis demonstrated that AMPK and PPARα were potential targets for CAVAF in alleviating obesity. Animal studies demonstrated that CAVAF intervention significantly decreased the body weight, WAT weight, serum TG, TC and LDL-C levels in HFD-fed obese mice. HFD-induced insulin resistance and morphological changes in WAT and brown adipose tissue were also markedly attenuated by CAVAF treatment. CAVAF supplementation potently inhibited iWAT inflammation by regulating IL-6, IL-1ß, TNF-α and IL-10 mRNA expression in iWAT of mice. Furthermore, the gene expression levels of thermogenic markers including Cyto C, ATP synthesis, Cidea, Cox8b and especially UCP1 in iWAT of mice were significantly up-regulated by CAVAF administration. CAVAF intervention also markedly increased the expression levels of PRDM16, PGC-1α, SIRT1, AMPK-α1, PPARα and PPARγ mRNA in iWAT of mice. CONCLUSION: CAVAF treatment significantly promoted browning of WAT in HFD-fed mice. These results suggested that flavonoid extracts from blossom of CAVA were probably promising candidates for the treatment of obesity.

Remodelling the inguinal adipose sensory system to switch on the furnace: Electroacupuncture stimulation induces brown adipose thermogenesis.

Brown and white adipose tissue mediate thermogenesis through the thermogenetic centre of the brain, but safe methods for activating thermogensis and knowledge of the associated molecular mechanisms are lacking. We investigated body surface electroacupuncture stimulation (ES) at ST25 (targeted at the abdomen) induction of brown adipose thermogenesis and the neural mechanism of this process. Inguinal white adipose tissue (iWAT) and interscapular brown adipose tissue (iBAT) were collected and the thermogenic protein expression levels were measured to evaluate iBAT thermogenesis capacity. The thermogenic centre activating region and sympathetic outflow were evaluated based on neural electrical activity and c-fos expression levels. iWAT sensory axon plasticity was analysed with whole-mount adipose tissue imaging. ES activated the sympathetic nerves in iBAT and the c-fos-positive cells induced sympathetic outflow activation to the iBAT from the medial preoptic area (MPA), the dorsomedial hypothalamus (DM) and the raphe pallidus nucleus (RPA). iWAT denervation mice exhibited decreased c-fos-positive cells in the DM and RPA, and lower recombinant uncoupling orotein 1 peroxisome proliferator-activated receptor, ß3-adrenergic receptor, and tyrosine hydroxylase expression. Remodelling the iWAT sensory axons recovered the signal from the MPA to the RPA and induced iBAT thermogenesis. The sympathetic denervation attenuated sensory nerve density. ES induced sympathetic outflow from the thermogenetic centres to iBAT, which mediated thermogenesis. iWAT sensory axon remodelling induced the MPA-DM-RPA-iBAT thermogenesis pathway.

Tibetan tea consumption prevents obesity by modulating the cellular composition and metabolic reprogramming of white adipose tissue.

Obesity, a global health concern, is linked with numerous metabolic and inflammatory disorders. Tibetan tea, a traditional Chinese beverage rich in theabrownin, is investigated in this study for its potential anti-obesity effects. Our work demonstrates that Tibetan tea consumption in C57BL/6J mice significantly mitigates obesity-related phenotypic changes without altering energy intake. Computational prediction revealed that Tibetan tea consumption reconstructs gene expression in white adipose tissue (WAT), promoting lipid catabolism and thereby increasing energy expenditure. We also note that Tibetan tea suppresses inflammation in WAT, reducing adipocyte hyperplasia and immune cell infiltration. Furthermore, Tibetan tea induces profound metabolic reprogramming, influencing amino acid metabolic pathways, specifically enhancing glutamine synthesis, which in turn suppresses pro-inflammatory chemokine production. These findings highlight Tibetan tea as a potential candidate in obesity prevention, providing a nuanced understanding of its capacity to modulate the cellular composition and metabolic landscape of WAT.

Dietary Achievable Dose of Protocatechuic Acid, a Metabolite of Flavonoids, Inhibits High-Fat Diet-Induced Obesity in Mice.

SCOPE: Protocatechuic acid (PCA), a gut microbiota metabolite of flavonoids, inhibits dietary obesity and increases uncoupling protein 1 (UCP1), a critical regulator responsible for adipose thermogenesis; however, these effects are achieved at dietary unachievable (pharmacological) dose. It evaluates whether dietary achievable dose of PCA inhibits adiposity by activating adipose thermogenesis. METHODS AND RESULTS: Six-week-old male C57BL/6J mice are fed a high-fat diet (HFD) alone (control) or supplemented with 0.003% PCA w/w for 16 weeks. PCA consumption does not affect food intake but appreciably reduces body weight gain, improves insulin sensitivity, and attenuates hepatic steatosis. These effects are associated with no significant changes in the abundance of UCP1 in adipose tissues. Instead, PCA consumption increases the abundance and enzymatic activity of carnitine palmitoyltransferase 1 (the first rate-limiting enzyme in fatty acid oxidation) in the livers, inguinal white, and brown adipose tissues. Surprisingly, PCA at physiologically achievable dose does not affect the abundance and enzymatic activity of carnitine acyltransferase-1 expression and the capacity of fatty acid oxidation in 3T3-L1-derived white or brown adipocytes and human hepatoma HepG2 cells. CONCLUSIONS: Dietary achievable dose of PCA attenuates HFD-induced adiposity, which is likely achieved by increasing fatty acid oxidation other than activating adipose thermogenesis.

Fish oil-derived n-3 polyunsaturated fatty acids downregulate aquaporin 9 protein expression of liver and white adipose tissues in diabetic KK mice and 3T3-L1 adipocytes.

Aquaporin 9 (AQP9) is an integral membrane protein that facilitates glycerol transport in hepatocytes and adipocytes. Glycerol is necessary as a substrate for gluconeogenesis in the physiological fasted state, suggesting that inhibiting AQP9 function may be beneficial for treating type 2 diabetes associated with fasting hyperglycemia. The n-3 polyunsaturated fatty acids (PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are rich in fish oil and lower the risk of metabolic syndrome; however, the effects of EPA and DHA on AQP9 expression in obese and type 2 diabetes are unclear. The KK mouse is an animal model of obesity and type 2 diabetes because of the polymorphisms on leptin receptor gene, which results in a part of cause for obese and diabetic conditions. In this study, we determined the effect of fish oil-derived n-3 PUFA on AQP9 protein expression in the liver and white adipose tissue (WAT) of KK mice and mouse 3T3-L1 adipocytes. The expression of AQP9 protein in the liver, epididymal WAT, and inguinal WAT were markedly decreased following fish oil administration. We also demonstrated that n-3 PUFAs, such as DHA, and to a lesser extent EPA, downregulated AQP9 protein expression in 3T3-L1 adipocytes. Our results suggest that fish oil-derived n-3 PUFAs may regulate the protein expressions of AQP9 in glycerol metabolism-related organs in KK mice and 3T3-L1 adipocytes.

Tracers and Imaging of Fatty Acid and Energy Metabolism of Human Adipose Tissues.

White adipose tissue and brown adipose tissue (WAT and BAT) regulate fatty acid metabolism and control lipid fluxes to other organs. Dysfunction of these key metabolic processes contributes to organ insulin resistance and inflammation leading to chronic diseases such as type 2 diabetes, metabolic dysfunction-associated steatohepatitis, and cardiovascular diseases. Metabolic tracers combined with molecular imaging methods are powerful tools for the investigation of these pathogenic mechanisms. Herein, I review some of the positron emission tomography and magnetic resonance imaging methods combined with stable isotopic metabolic tracers to investigate fatty acid and energy metabolism, focusing on human WAT and BAT metabolism. I will discuss the complementary strengths offered by these methods for human investigations and current gaps in the field.

[Effect and mechanism of Zexie Decoction in promoting white adipose tissue browning/brown adipose tissue activation based on GLP-1R/cAMP/PKA/CREB pathway].

This study investigated the mechanism of Zexie Decoction(ZXD) in promoting white adipose tissue browning/brown adipose tissue activation based on the GLP-1R/cAMP/PKA/CREB pathway. A hyperlipidemia model was induced by a western diet(WD) in mice, and the mice were divided into a control group, a model group(WD), and low-, medium-, and high-dose ZXD groups. An adipogenesis model was induced in 3T3-L1 cells in vitro, and with forskolin(FSK) used as a positive control, low-, medium-, and high-dose ZXD groups were set up. Immunohistochemistry and immunofluorescence results showed that compared with the WD group, ZXD promoted the expression of UCP1 in white and brown adipose tissues, and also upregulated UCP1, CPT1ß, PPARα, and other genes in the cells. Western blot analysis showed a dose-dependent increase in the protein expression of PGC-1α, UCP1, and PPARα with ZXD treatment, indicating that ZXD could promote the white adipose tissue browning/brown adipose tissue activation. Hematoxylin-eosin(HE) staining results showed that after ZXD treatment, white and brown adipocytes were significantly reduced in size, and the mRNA expression of ATGL, HSL, MGL, and PLIN1 was significantly upregulated as compared with the results in the WD group. Oil red O staining and biochemical assays indicated that ZXD improved lipid accumulation and promoted lipolysis. Immunohistochemistry and immunofluorescence staining for p-CREB revealed that ZXD reversed the decreased expression of p-CREB caused by WD. In vitro intervention with ZXD increased the protein expression of CREB, p-CREB, and p-PKA substrate, and increased the mRNA level of CREB. ELISA detected an increase in intracellular cAMP concentration with ZXD treatment. Molecular docking analysis showed that multiple active components in Alismatis Rhizoma and Atractylodis Macrocephalae Rhizoma could form stable hydrogen bond interactions with GLP-1R. In conclusion, ZXD promotes white adipose tissue browning/brown adipose tissue activation both in vivo and in vitro, and its mechanism of action may be related to the GLP-1R/cAMP/PKA/CREB pathway.

Mulberry leaf flavonoids activate BAT and induce browning of WAT to improve type 2 diabetes via regulating the AMPK/SIRT1/PGC-1α signaling pathway.

Mulberry (Morus alba L.) leaf is a well-established traditional Chinese botanical and culinary resource. It has found widespread application in the management of diabetes. The bioactive constituents of mulberry leaf, specifically mulberry leaf flavonoids (MLFs), exhibit pronounced potential in the amelioration of type 2 diabetes (T2D). This potential is attributed to their ability to safeguard pancreatic ß cells, enhance insulin resistance, and inhibit α-glucosidase activity. Our antecedent research findings underscore the substantial therapeutic efficacy of MLFs in treating T2D. However, the precise mechanistic underpinnings of MLF's anti-T2D effects remain the subject of inquiry. Activation of brown/beige adipocytes is a novel and promising strategy for T2D treatment. In the present study, our primary objective was to elucidate the impact of MLFs on adipose tissue browning in db/db mice and 3T3-L1 cells and elucidate its underlying mechanism. The results manifested that MLFs reduced body weight and food intake, alleviated hepatic steatosis, improved insulin sensitivity, and increased lipolysis and thermogenesis in db/db mice. Moreover, MLFs activated brown adipose tissue (BAT) and induced the browning of inguinal white adipose tissue (IWAT) and 3T3-L1 adipocytes by increasing the expressions of brown adipocyte marker genes and proteins such as uncoupling protein 1 (UCP1) and beige adipocyte marker genes such as transmembrane protein 26 (Tmem26), thereby promoting mitochondrial biogenesis. Mechanistically, MLFs facilitated the activation of BAT and the induction of WAT browning to ameliorate T2D primarily through the activation of AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1)/peroxisome proliferator-activated receptor-gamma coactivator 1α (PGC-1α) signaling pathway. These findings highlight the unique capacity of MLF to counteract T2D by enhancing BAT activation and inducing browning of IWAT, thereby ameliorating glucose and lipid metabolism disorders. As such, MLFs emerge as a prospective and innovative browning agent for the treatment of T2D.

Integrated UHPLC-QE/MS, transcriptomics and network pharmacology reveal the mechanisms via which Liang-Yan-Yi-Zhen-San promotes the browning of white adipose tissue.

We have previously shown that Liang-Yan-Yi-Zhen-San (LYYZS), an ancient Chinese herbal formula, can promote the browning of white adipose tissue. In this study, we sought to determine which active ingredients of LYYZS mediated its effects on the browning of white adipose tissue. Employing ultra-high performance liquid chromatography-Q-Exactive HF mass spectrometry, a total of 52 LYYZS ingredients were identified. On this basis, 1,560 ingredient-related targets of LYYZS were screened using the HERB databases. Meanwhile, RNA sequencing analysis of the inguinal white adipose tissue of mice produced a total of 3148 genes that were significantly differentially expressed following LYYZS treatment and differentially expressed genes regarded as browning-related targets. Through the network pharmacological analysis, a total of 136 intersection targets were obtained and an ingredient-target-pathway network was established. According to network pharmacology analysis, 10 ingredients containing trans-cinnamaldehyde, genistein, daidzein, calycosin, arginine, coumarin, oleic acid, isoleucine, palmitic acid and tyrosine were regarded as active ingredients of browning of white adipose tissue. Integrated evaluation using chemical analysis, transcriptomics and network pharmacology provides an efficient strategy for discovering the active ingredients involved in how LYYZS promotes the browning of white adipose tissue.

DHA alleviated hepatic and adipose inflammation with increased adipocyte browning in high-fat diet-induced obese mice.

Obesity is associated with accumulation of inflammatory immune cells in white adipose tissue, whereas thermogenic browning adipose tissue is inhibited. Dietary fatty acids are important nutritional components and several clinical and experimental studies have reported beneficial effects of docosahexaenoic acid (DHA) on obesity-related metabolic changes. In this study, we investigated effects of DHA on hepatic and adipose inflammation and adipocyte browning in high-fat diet-induced obese C57BL/6J mice, and in vitro 3T3-L1 preadipocyte differentiation. Since visceral white adipose tissue has a close link with metabolic abnormality, epididymal adipose tissue represents current target for evaluation. A course of 8-week DHA supplementation improved common phenotypes of obesity, including improvement of insulin resistance, inhibition of macrophage M1 polarization, and preservation of macrophage M2 polarization in hepatic and adipose tissues. Moreover, dysregulated adipokines and impaired thermogenic and browning molecules, considered obesogenic mechanisms, were improved by DHA, along with parallel alleviation of endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and mitochondrial DNA stress-directed innate immunity. During 3T3-L1 preadipocytes differentiation, DHA treatment decreased lipid droplet accumulation and increased the levels of thermogenic, browning, and mitochondrial biogenesis molecules. Our study provides experimental evidence that DHA mitigates obesity-associated inflammation and induces browning of adipose tissue in visceral epididymal adipose tissue. Since obesity is associated with metabolic abnormalities across tissues, our findings indicate that DHA may have potential as part of a dietary intervention to combat obesity.

Hydroxy-α-sanshool from the fruits of Zanthoxylum bungeanum Maxim. promotes browning of white fat by activating TRPV1 to induce PPAR-γ deacetylation.

BACKGROUND: Accumulating evidence suggested increasing energy expenditure is a feasible strategy for combating obesity, and browning of white adipose tissue (WAT) to promote thermogenesis might be one of the attractive ways. Hydroxy-α-sanshool (HAS), a natural amide alkaloid extracted from the fruits of Zanthoxylum bungeanum Maxim, possesses lots of benefits in lipid metabolism regulation. METHODS: The anti-obesity effect of HAS was investigated by establishing an animal model of obesity and a 3T3-L1 differentiation cell model. Effects of HAS on the whole-body fat and liver of obese mice, and the role of HAS in inducing browning of white fat were studied by Micro CT, Metabolic cage detection, Cell mitochondrial pressure detection, transmission electron microscopy and cold exposure assays. Furthermore, the Real-time PCR (qPCR), digital PCR (dPCR), western blot, Co-immunoprecipitation (Co-IP), molecular docking, drug affinity responsive target stability (DARTS), Cellular thermal shift assay (CETSA) and other methods were used to investigate the target and mechanisms of HAS. RESULTS: We found that treatment with HAS helped mice combat obesity caused by a high fat diet (HFD) and improve metabolic characteristics. In addition, our results suggested that the anti-obesity effect of HAS is related to increase energy consumption and thermogenesis via induction of browning of WAT. The further investigations uncovered that HAS can up-regulate UCP-1 expression, increase mitochondria number, and elevate the cellular oxygen consumption rates (OCRs) of white adipocytes. Importantly, the results indicated that browning effects of HAS is closely associated with SIRT1-dependent PPAR-γ deacetylation through activating the TRPV1/AMPK pathway, and TRPV1 is the potential drug target of HAS for the browning effects of WAT. CONCLUSIONS: Our results suggested the HAS can promote browning of WAT via regulating AMPK/SIRT-1/PPARγ signaling, and the potential drug target of HAS is the membrane receptor of TRPV1.

Low Dose of Curcumin Combined with Exercise Synergistically Induces Beige Adipocyte Formation in Mice.

Curcumin (Cur) has various biological effects, including anti-obesity and anti-diabetic properties. However, the molecular mechanisms by which Cur exerts these effects remain unclear. In addition, high doses of Cur have been administered in most animal and human trials to date, due mainly to the poor water solubility of native Cur and its low oral bioavailability. In our previous study, we demonstrated that a highly bioavailable Cur formulation (4.5 mg/kg) induces the formation of beige adipocytes in inguinal white adipose tissue (iWAT) in mice. In the present study, to enhance Cur-mediated beige adipocyte formation and reduce the required functional Cur dose, we investigated whether a low dose of Cur combined with exercise synergistically induced beige adipocyte formation. Cur (1.5 mg Cur/kg, daily) combined with exercise for 4 wk significantly induced beige adipocyte formation in iWAT in mice. This effect was associated with the elevation of interleukin-6 level following subsequent Cur administration combined with exercise. These results indicate that exercise combined with Cur synergistically enhances biological activity and reduces the required Cur dose. These findings suggest that Cur could be used as a dietary supplement during exercise to enhance exercise-mediated health benefits.

[Electroacupuncture improves obesity and promotes white adipose tissue browning by regulating central glucagon-like peptide-1].

OBJECTIVE: To observe the effect of electroacupuncture （EA） on white adipose tissue （WAT） browning by regulating central glucagon-like peptide-1 （GLP-1）, so as to explore the possible central mechanisms of EA in improving obesity. METHODS: Thirty male Wistar rats were randomly divided into normal group, model group, EA group, HM3D group, and EA+HM4D group, with 6 rats in each group. The obesity rat model was obtained by feeding with high-fat diet for 8 weeks. Adeno-associated virus combined with DREADDs was injected into bilateral nucleus of solitary tract （NTS）, with rAAV-GLP-1+rAAV-4D applied to the EA+HM4D group, rAAV-GLP-1+rAAV-3D applied to the HM3D group, and rAAV-GLP-1+rAAV-GFP applied to other 3 groups. After modeling, rats in the EA and EA+HM4D groups received EA treatment at bilateral "Zusanli"（ST36）, "Fenglong"（ST40）, "Guanyuan"（CV4） and "Zhongwan"（CV12）, with successive waves （2 Hz, 1 mA） for 10 minutes, 3 times a week, for a total of 8 weeks. Body mass of rats in each group were measured before and 2, 4, 6, and 8 weeks after intervention. Abdominal and perirenal WAT mass was weighed, serum triglyceride （TG） and total cholesterol （TC） contents were detected by using automatic analyzer, and nonestesterified fatty acid （NEFA） content was detected by using colorimetric assay kit. The morphology of abdominal WAT lipid droplets was observed by HE staining. The mRNA expressions of GLP-1 in NTS, AMPK in ventromedial nucleus of hypothalamus（VMH）, UCP1 and PGC-1α in subcutaneous fat were detected by real-time PCR. The protein expression levels of GLP-1, AMPK, phosphorylated-AMPK, UCP1 and PGC-1α were detected by Western blot. The activation level of GLP-1 neurons in NTS was observed by immunofluorescence. RESULTS: Compared with the normal group, abdominal WAT lipid droplets were enlarged, body weight, serum TG, TC, NEFA contents, abdominal and perirenal WAT mass, mRNA and protein expression levels of AMPK were significantly increased（P<0.01, P<0.05）, while GLP-1 neurons activation level, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and AMPK protein phosphorylation were decreased （P<0.01） in the model group. After EA intervention, body weight at 6 and 8 weeks after intervention and other indexes mentioned above were all significantly reversed （P<0.01, P<0.05） in the EA group in comparison with those of the model group. Compared with the EA group, the HM3D group had reduced abdominal WAT lipid droplets size, decreased serum TG, TC, and NEFA contents, and protein expression level of AMPK（P<0.01, P<0.05）, with increased mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α, and phosphorylation level of AMPK protein（P<0.01, P<0.05）, while the EA+HM4D group had enlarged abdominal WAT lipid droplets, increased body weight 6 and 8 weeks after intervention, abdominal and renal WAT mass, and NEFA content （P<0.01, P<0.05）, with decreased serum TG content, activation level of GLP-1 neurons in the NTS, mRNA and protein expression levels of GLP-1, UCP1 and PGC-1α （P<0.01, P<0.05）, as well as down-regulated phosphorylation of AMPK protein and mRNA （P<0.01, P<0.05）. CONCLUSION: EA can effectively promote the browning of WAT, which may be related to the activation of GLP-1 neurons in the NTS, as well as the promotion of the phosphorylation of AMPK in the VMH and up-regulation of UCP1.