Rubi Fructus (Rubus coreanus) activates the expression of thermogenic genes in vivo and in vitro

Thermogenic adipose tissues: Promising therapeutic targets for metabolic diseases

The ongoing increase in the prevalence of obesity and its comorbidities such as cardiovascular disease, type 2 diabetes (T2D) and dyslipidemia warrants discovery of novel therapeutic options for these metabolic diseases. Obesity is characterized by white adipose tissue expansion due to chronic positive energy balance as a result of excessive energy intake and/or reduced energy expenditure. Despite various efforts to prevent or reduce obesity including lifestyle and behavioral interventions, surgical weight reduction approaches and pharmacological methods, there has been limited success in significantly reducing obesity prevalence. Recent research has shown that thermogenic adipocyte (brown and beige) activation or formation, respectively, could potentially act as a therapeutic strategy to ameliorate obesity and its related disorders. This can be achieved through the ability of these thermogenic cells to enhance energy expenditure and regulate circulating levels of glucose and lipids. Thus, unraveling the molecular mechanisms behind the formation and activation of brown and beige adipocytes holds the potential for probable therapeutic paths to combat obesity. In this review, we provide a comprehensive update on the development and regulation of different adipose tissue types. We also emphasize recent interventions in harnessing therapeutic potential of thermogenic adipocytes by bioactive compounds and new pharmacological anti-obesity agents.

4-hydroxybenzoic acid induces browning of white adipose tissue through the AMPK-DRP1 pathway in HFD-induced obese mice

BACKGROUND

Beige adipocytes have physiological functions similar to brown adipocytes, which are available to increase energy expenditure through uncoupling protein 1 (UCP1) within mitochondria. Recently, many studies showed white adipocytes can undergo remodeling into beige adipocytes, called "browning", by increasing fusion and fission events referred to as mitochondrial dynamics.

PURPOSE

In this study, we aimed to investigate the browning effects of 4-hydroxybenzoic acid (4-HA), one of the major compounds of black raspberries.

METHODS

We examined the mechanism underlying the browning properties of 4-HA focusing on UCP1-dependent non-shivering thermogenesis in 3T3-L1 white adipocytes, high-fat diet (HFD)-induced obese male C57BL/6J mice, and cold-exposed male C57BL/6J mice.

RESULTS

4-HA treatment elevates browning markers such as UCP1, T-Box transcription factor 1, and PR domain containing 16, mitochondrial function factors like oxidative phosphorylation complex as well as mitochondrial dynamic-related factors like phosphorylated dynamin-related protein 1 (p-DRP1), DRP1, and mitofusin 1 in 3T3-L1 white adipocytes, which were also confirmed in inguinal white adipose tissue (iWAT) of HFD-induced obese mice. Mdivi-1 blocked the increased DRP1-mediated mitochondrial fission by 4-HA, and even the browning effect of 4-HA was abolished. Furthermore, 4-HA increased AMP-activated protein kinase (AMPK) in both the 3T3-L1 white adipocytes and iWAT of HFD-induced obese mice. Inhibition of AMPK with Compound C also blocked the 4-HA-induced mitochondrial fission and browning effect.

CONCLUSIONS

4-HA induces the browning of white adipocytes into beige adipocytes by regulating the DRP1-mediated mitochondrial dynamics through AMPK. These findings suggest that 4-HA could serve as a therapeutic candidate for obesity and related metabolic disorders.

Lycium chinense Mill Induces Anti-Obesity and Anti-Diabetic Effects In Vitro and In Vivo

This study investigated the effects of Lycium chinense Mill (LCM) extract on obesity and diabetes, using both in vitro and high-fat diet (HFD)-induced obesity mouse models. We found that LCM notably enhanced glucagon-like peptide-1 (GLP-1) secretion in NCI-h716 cells from 411.4 ± 10.75 pg/mL to 411.4 ± 10.75 pg/mL compared to NT (78.0 ± 0.67 pg/mL) without causing cytotoxicity, implying the involvement of Protein Kinase A C (PKA C) and AMP-activated protein kinase (AMPK) in its action mechanism. LCM also decreased lipid droplets and lowered the expression of adipogenic and lipogenic indicators, such as Fatty Acid Synthase (FAS), Fatty Acid-Binding Protein 4 (FABP4), and Sterol Regulatory Element-Binding Protein 1c (SREBP1c), indicating the suppression of adipocyte differentiation and lipid accumulation. LCM administration to HFD mice resulted in significant weight loss (41.5 ± 3.3 g) compared to the HFD group (45.1 ± 1.8 g). In addition, improved glucose tolerance and serum lipid profiles demonstrated the ability to counteract obesity-related metabolic issues. Additionally, LCM exhibited hepatoprotective properties by reducing hepatic lipid accumulation and diminishing white adipose tissue mass and adipocyte size, thereby demonstrating its effectiveness against hepatic steatosis and adipocyte hypertrophy. These findings show that LCM can be efficiently used as a natural material to treat obesity and diabetes, providing a new approach for remedial and therapeutic purposes.

Dysfunction of the Brown Adipose Organ in HFD-Obese Rats and Effect of Tart Cherry Supplementation

Obesity has a great impact on adipose tissue biology, based on its function as a master regulator of energy balance. Brown adipose tissue (BAT) undergoes remodeling, and its activity declines in obese subjects due to a whitening process. The anti-obesity properties of fruit extracts have been reported. The effects of tart cherry against oxidative stress, inflammation, and the whitening process in the BAT of obese rats were investigated. Intrascapular BAT (iBAT) alterations and effects of Prunus cerasus L. were debated in rats fed for 17 weeks with a high-fat diet (DIO), in DIO supplemented with seed powder (DS), and with seed powder plus the juice (DJS) of tart cherry compared to CHOW rats fed with a normo-caloric diet. iBAT histologic observations revealed a whitening process in DIO rats that was reduced in the DS and DJS groups. A modulation of uncoupling protein-1 (UCP-1) protein and gene expression specifically were detected in the obese phenotype. An upregulation of UCP-1 and related thermogenic genes after tart cherry intake was detected compared to the DIO group. Metabolic adjustment, endoplasmic reticulum stress, protein carbonylation, and the inflammatory microenvironment in the iBAT were reported in DIO rats. The analysis demonstrated an iBAT modulation that tart cherry promoted. In addition to our previous results, these data confirm the protective impact of tart cherry consumption on obesity.

An update on brown adipose tissue and obesity intervention: Function, regulation and therapeutic implications

Overweight and obesity have become a world-wide problem. However, effective intervention approaches are limited. Brown adipose tissue, which helps maintain body temperature and contributes to thermogenesis, is dependent on uncoupling protein1. Over the last decade, an in-creasing number of studies have found that activating brown adipose tissue and browning of white adipose tissue can protect against obesity and obesity-related metabolic disease. Brown adipose tissue has gradually become an appealing therapeutic target for the prevention and re-versal of obesity. However, some important issues remain unresolved. It is not certain whether increasing brown adipose tissue activity is the cause or effect of body weight loss or what the risks might be for sympathetic nervous system-dependent non-shivering thermogenesis. In this review, we comprehensively summarize approaches to activating brown adipose tissue and/or browning white adipose tissue, such as cold exposure, exercise, and small-molecule treatment. We highlight the functional mechanisms of small-molecule treatment and brown adipose tissue transplantation using batokine, sympathetic nervous system and/or gut microbiome. Finally, we discuss the causality between body weight loss induced by bariatric surgery, exercise, and brown adipose tissue activity.

Natural Extracts That Stimulate Adipocyte Browning and Their Underlying Mechanisms

Despite progress in understanding the developmental lineage and transcriptional factors regulating brown and beige adipocytes, the role of environmental modifiers, such as food components and natural extracts, remains to be elucidated. Furthermore, the undesirable pleiotropic effects produced by synthetic drugs targeting adipose tissue browning and thermogenesis necessitate research into alternative natural sources to combat obesity and related metabolic disorders. The current review, therefore, focused on the effects of various extracts from foods, plants, and marine products on adipose tissue browning and obesity. In particular, the recent findings of food components and marine products on adipose tissue browning will be discussed here.

Farnesol induces mitochondrial/peroxisomal biogenesis and thermogenesis by enhancing the AMPK signaling pathway in vivo and in vitro

Thermogenic activation of brown adipose tissue has been considered as an obesity treatment strategy that consumes energy. In this study, we investigated whether farnesol in vivoandin vitro models induces thermogenesis and affect the activation of the mitochondria and peroxisomes, which are key organelles in activated brown adipocytes. Farnesol induced the expression of thermogenic factors such as uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor γ coactivator 1 alpha (PGC1α), and PR domain zinc-finger protein 16 (PRDM16) together with the phosphorylation of AMP-activated protein kinase alpha (AMPKα) in brown adipose tissue and primary cultured brown adipocytes. Farnesol promoted lipolytic enzymes: hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL). We confirmed that these inductions of lipolysis by farnesol were the underlying causes of β-oxidation activation. Farnesol also increased the expression of oxidative phosphorylation (OXPHOS) complexes and the oxygen consumption rate (OCR) and the expansion of peroxisomes. Moreover, we proved that the thermogenic activity of farnesol was dependent on AMPKα activation using Compound C inhibitor or siRNA-AMPKα knockdown. These results suggest that farnesol may be a potential agent for the treatment of obesity by inducing energy consumption through heat generation.

A phytoestrogen secoisolariciresinol diglucoside induces browning of white adipose tissue and activates non-shivering thermogenesis through AMPK pathway

Secoisolariciresinol diglucoside (SDG) is the main phytoestrogen component of flaxseed known as an antioxidant. Current study focused on the effect of SDG in white adipose tissue (WAT) browning. Browning of WAT is considered as a promising treatment strategy for metabolic diseases. To demonstrate the effect of SDG as an inducer of browning, brown adipocyte markers were investigated in inguinal WAT (iWAT) of high fat diet-fed obese mice and genetically obese db/db mice after SDG administration. SDG increased thermogenic factors such as uncoupling protein 1, peroxisome proliferator-activated receptor gamma coactivator 1 alpha and PR domain containing 16 in iWAT and brown adipose tissue (BAT) of mice. Similar results were shown in beige-induced 3T3-L1 adipocytes and primary cultured brown adipocytes. Furthermore, SDG increased factors of mitochondrial biogenesis and activation. We also observed SDG-induced alteration of AMP-activated protein kinase α (AMPKα). As AMPKα is closely related in the regulation of adipogenesis and thermogenesis, we then evaluated the effect of SDG in AMPKα-inhibited conditions. Genetic or chemical inhibition of AMPKα demonstrated that the role of SDG on browning and thermogenesis was dependent on AMPKα signaling. In conclusion, our data suggest SDG as a potential candidate for improvement of obesity and other metabolic disorders.

Jiang Gui Fang activated interscapular brown adipose tissue and induced epididymal white adipose tissue browning through the PPARγ/SIRT1-PGC1α pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Gui Zhi Tang, a well-known Chinese herbal formula recorded in the Eastern Han Dynasty, has been widely used to treat exogenous cold for thousands of years. Recent studies have shown that Gui Zhi Tang has the effect of regulating the body temperature. Because of its effect on heat production, protecting vital organs of the body and avoiding damage from the cold environment, Jiang Gui Fang (JG) was obtained from the Department of Traditional Chinese Medicine at the General Hospital of Northern Theatre Command where it has been used clinically for many years and has exhibited favourable efficacy. Based on research on Gui Zhi Tang, the principles of traditional Chinese medicine and survey of a large number of studies, this empirical formula was developed. The composition of JG included Dried ginger, Cassia twig, and Liquorice in Gui Zhi Tang, which play a major role in the treatment of exogenous cold, and combined these components with other Chinese medicines, such as Pueraria, Spatholobus, Acanthopanacis cortex, Evodiae fructus, and Codonopsis pilosula.

AIM OF THE STUDY

To promote the core body temperature and prevent invasion of the major organs from the cold environment, we studied the effect of JG on the core body temperature of mice and then explored its regulation of interscapular brown adipose tissue (iBAT) and epididymal white adipose tissue (eWAT) and the possible mechanism. Finally, we determined the phytochemical composition of JG that plays a role in heat production.

MATERIALS AND METHODS

In vivo study, we performed a 4-week treatment of JG in acute cold environment at -20 °C and chronic cold exposure at 4 °C. The core temperature, adipose tissue weight, serum parameters, and morphological observation of adipocytes, liver and kidney were measured. Then we investigated the expression levels of adipogenic factors, thermogenic factors and lipoprotein. In vitro, we determined the lipid droplet content, ATP content, and the maximum oxygen consumption of mitochondria.

RESULTS

JG treatment promoted core temperature, inhibited eWAT weight, protected liver, and reduced glucose and lipids in Kunming (KM) mice. JG also increased the expression of BAT-associated thermogenic factors, including uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor γ coactivator-1α (PGC1α). The levels of the lipogenic factor peroxisome proliferate-activator receptor gamma (PPARγ) and the lipolytic protein hormone-sensitive triglyceride lipase (HSL) in eWAT were elevated. The results of H&E and immunohistochemistry showed that JG significantly reduced the size of iBAT and eWAT and increased the content of UCP1. In vitro, JG reduced the content of lipid droplets and ATP in brown fat cells. The maximum oxygen consumption capacity of mitochondria and the expression levels of UCP1, PGC1α and silent mating type information regulation 2 homologue 1 (SIRT1) were enhanced after JG treatment.

CONCLUSIONS

In vivo and in vitro studies, the results demonstrated that JG obviously increased the core temperature of mice by activating iBAT and inducing eWAT browning, which proved the mechanism is closely related to the PPARγ/SIRT1- PGC1α pathway. In this paper, we will provide a reference for further study of iBAT activation and eWAT browning.

ZW290 Increases Cold Tolerance by Inducing Thermogenesis via the Upregulation of Uncoupling Protein 1 in Brown Adipose Tissue In Vitro and In Vivo

To provide molecular evidence on the thermogenic mechanism of primary brown adipocytes, western blot analysis was used to detect brown adipose tissue (BAT)-specific gene expressions. BAT protects the mammals from hypothermia injury with a large amount of mitochondria and high expression of uncoupling Protein 1 (UCP1), which is the vital protein to determine the heat production in BAT. In our previous study, the compound ZW290 (the structure shown in Fig. 1) was obtained by molecular docking with a UCP1 inducer. In the present study, ZW290 not only significantly upregulated the expression of UCP1 protein (p < 0.01) and its related signaling pathway in the primary brown adipocytes, but also remarkably decreased the mitochondrial membrane potential and the concentration of adenosine triphosphate (ATP) (p < 0.01). Kunming (KM) mice were kept under acute cold exposure (-20°C) to evaluate the preventive and protective effects of ZW290 on cold injury, and revealed its regulating mechanism in vitro. The rectal and body temperatures of ZW290-treated mice were significantly higher than those of the control (or model) group both at room temperature and at -20°C (p < 0.001). Hematoxylin-eosin (HE) staining and immunohistochemistry indicated that ZW290 notably decreased the size of lipid droplets in BAT and increased the content of mitochondria and the expression of UCP1 in BAT and white adipose tissue (WAT). Furthermore, the survival rate showed that ZW290 could prolong the overall survival of mice. Therefore, we obtained the conclusion that ZW290 might transform energy into heat by inhibiting ATP synthesis and increasing the expression of UCP1. Additionally, ZW290 may enhance cold tolerance by increasing heat production through increasing the content of mitochondria and the expression of UCP1 in BAT and WAT.

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.

Synergistic Effect of Bupleuri Radix and Scutellariae Radix on Adipogenesis and AMP-Activated Protein Kinase: A Network Pharmacological Approach

Obesity has become a major health threat in developed countries. However, current medications for obesity are limited because of their adverse effects. Interest in natural products for the treatment of obesity is thus rapidly growing. Korean medicine is characterized by the wide use of herbal formulas. However, the combination rule of herbal formulas in Korean medicine lacks experimental evidence. According to Shennong's Classic of Materia Medica, the earliest book of herbal medicine, Bupleuri Radix (BR) and Scutellariae Radix (SR) possess the Sangsoo relationship, which means they have synergistic features when used together. Therefore these two are frequently used together in prescriptions such as Sosiho-Tang. In this study, we used the network pharmacological method to predict the interaction between these two herbs and then investigated the effects of BR, SR, and their combination on obesity in 3T3-L1 adipocytes. BR, SR, and BR-SR mixture significantly decreased lipid accumulation and the expressions of two major adipogenic factors, peroxisome proliferator-activated receptor-gamma (PPARγ) and CCAAT/enhancer-binding protein-alpha (C/EBPα), and their downstream genes, Adipoq, aP2, and Lipin1 in 3T3-L1 cells. In addition, the BR-SR mixture had synergistic effects compared with BR or SR on inhibition of adipogenic-gene expressions. BR and SR also inhibited the protein expressions of PPARγ and C/EBPα. Furthermore, the two extracts successfully activated AMP-activated protein kinase alpha (AMPK α), the key regulator of energy metabolism. When compared to those of BR or SR, the BR-SR mixture showed higher inhibition rates of PPARγ and C/EBPα, along with higher activation rate of AMPK. These results indicate a new potential antiobese pharmacotherapy and also provide scientific evidence supporting the usage of herbal combinations instead of mixtures in Korean medicine.

Vanillic acid attenuates obesity via activation of the AMPK pathway and thermogenic factors in vivo and in vitro

Energy expenditure is a target gaining recent interest for obesity treatment. The antiobesity effect of vanillic acid (VA), a well-known flavoring agent, was investigated in vivo and in vitro. High-fat diet (HFD)-induced obese mice and genetically obese db/db mice showed significantly decreased body weights after VA administration. Two major adipogenic markers, peroxisome proliferator activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), were reduced while the key factor of energy metabolism, AMPKα, was increased in the white adipose tissue and liver tissue of VA-treated mice. Furthermore, VA inhibited lipid accumulation and reduced hepatotoxic/inflammatory markers in liver tissues of mice and HepG2 hepatocytes. VA treatment also decreased differentiation of 3T3-L1 adipocytes by regulating adipogenic factors including PPARγ and C/EBPα. AMPKα small interfering RNA was used to examine whether AMPK was associated with the actions of VA. In AMPKα-nulled 3T3-L1 cells, the inhibitory action of VA on PPARγ and C/EBPα was attenuated. Furthermore, in brown adipose tissues of mice and primary cultured brown adipocytes, VA increased mitochondria- and thermogenesis-related factors such as uncoupling protein 1 and PPARγ-coactivator 1-α. Taken together, our results suggest that VA has potential as an AMPKα- and thermogenesis-activating antiobesity agent.-Jung, Y., Park, J., Kim, H.-L., Sim, J.-E., Youn, D.-H., Kang, J., Lim, S., Jeong, M.-Y., Yang, W. M., Lee, S.-G., Ahn, K. S., Um, J.-Y. Vanillic acid attenuates obesity via activation of the AMPK pathway and thermogenic factors in vivo and in vitro.

Farnesol Has an Anti-obesity Effect in High-Fat Diet-Induced Obese Mice and Induces the Development of Beige Adipocytes in Human Adipose Tissue Derived-Mesenchymal Stem Cells

Brown adipocytes dissipate energy as heat and hence have an important therapeutic capacity for obesity. Development of brown-like adipocytes (also called beige) is also another attractive target for obesity treatment. Here, we investigated the effect of farnesol, an isoprenoid, on adipogenesis in adipocytes and on the browning of white adipose tissue (WAT) as well as on the weight gain of high-fat diet (HFD)-induced obese mice. Farnesol inhibited adipogenesis and the related key regulators including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein α through the up-regulation of AMP-activated protein kinase in 3T3-L1 murine adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). Farnesol markedly increased the expression of uncoupling protein 1 and PPARγ coactivator 1 α in differentiated hAMSCs. In addition, farnesol limited the weight gain in HFD obese mice and induced the development of beige adipocytes in both inguinal and epididymal WAT. These results suggest that farnesol could be a potential therapeutic agent for obesity treatment.

Natural alkaloid bouchardatine ameliorates metabolic disorders in high-fat diet-fed mice by stimulating the sirtuin 1/liver kinase B-1/AMPK axis

BACKGROUND AND PURPOSE

Promoting energy metabolism is known to provide therapeutic effects for obesity and associated metabolic disorders. The present study evaluated the therapeutic effects of the newly identified bouchardatine (Bou) on obesity-associated metabolic disorders and the molecular mechanisms of these effects.

EXPERIMENTAL APPROACH

The molecular mode of action of Bou for its effects on lipid metabolism was first examined in 3T3-L1 adipocytes and HepG2 cells. This was followed by an evaluation of its metabolic effects in mice fed a high-fat diet for 16 weeks with Bou being administered in the last 5 weeks. Further mechanistic investigations were conducted in pertinent organs of the mice and relevant cell models.

KEY RESULTS

In 3T3-L1 adipocytes, Bou reduced lipid content and increased sirtuin 1 (SIRT1) activity to facilitate liver kinase B1 (LKB1) activation of AMPK. Chronic administration of Bou (50 mg∙kg^-1 every other day) in mice significantly attenuated high-fat diet-induced increases in body weight gain, dyslipidaemia and fatty liver without affecting food intake and no adverse effects were detected. These metabolic effects were associated with activation of the SIRT1-LKB1-AMPK signalling pathway in adipose tissue and liver. Of particular note, UCP1 expression and mitochondrial biogenesis were increased in both white and brown adipose tissues of Bou-treated mice. Incubation with Bou induced similar changes in primary brown adipocytes isolated from mice.

CONCLUSIONS AND IMPLICATIONS

Bou may have therapeutic potential for obesity-related metabolic diseases by increasing the capacity of energy expenditure in adipose tissues and liver through a mechanism involving the SIRT1-LKB1-AMPK axis.

Myricetin protects against diet-induced obesity and ameliorates oxidative stress in C57BL/6 mice

BACKGROUND

Myricetin is a naturally occurring antioxidant commonly found in various plants. However, little information is available with respect to its direct anti-obesity effects.

OBJECTIVE

This study was undertaken to investigate the effect of myricetin on high-fat diet (HFD)-induced obesity in C57BL/6 mice.

RESULTS

Administration of myricetin dramatically reduced the body weight of diet-induced obese mice compared with solely HFD-induced mice. Several parameters related to obesity including serum glucose, triglyceride, and cholesterol were significantly decreased in myricetin-treated mice. Moreover, obesity-associated oxidative stress (glutathione peroxidase (GPX) activity, total antioxidant capacity (T-AOC), and malondialdehyde (MDA)) and inflammation (tumor necrosis factor-α (TNF-α)) were ameliorated in myricetin-treated mice. Further investigation revealed that the protective effect of myricetin against HFD-induced obesity in mice appeared to be partially mediated through the down-regulation of mRNA expression of adipogenic transcription factors peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer-binding protein α (C/EBPα), and lipogenic transcription factor sterol regulatory element-binding protein 1c (SREBP-1c).

CONCLUSIONS

Consumption of myricetin may help to prevent obesity and obesity-related metabolic complications.

Restoration of Declined Immune Responses and Hyperlipidemia by Rubus occidenalis in Diet-Induced Obese Mice

Hyperlipidemia, which is closely associated with a fatty diet and aging, is commonly observed in the western and aged society. Therefore, a novel therapeutic approach for this disease is critical, and an immunological view has been suggested as a novel strategy, because hyperlipidemia is closely associated with inflammation and immune dysfunction. In this study, the effects of an aqueous extract of Rubus occidentalis (RO) in obese mice were investigated using immunological indexes. The mice were fed a high-fat diet (HFD) to induce hyperlipidemia, which was confirmed by biochemical analysis and examination of the mouse physiology. Two different doses of RO and rosuvastatin, a cholesterol synthesis inhibitor used as a control, were orally administered. Disturbances in immune cellularity as well as lymphocyte proliferation and cytokine production were significantly normalized by oral administration of RO, which also decreased the elevated serum tumor necrosis factor (TNF)-α level and total cholesterol. The specific immune-related actions of RO comprised considerable improvement in cytotoxic T cell killing functions and regulation of antibody production to within the normal range. The immunological evidence confirms the significant cholesterol-lowering effect of RO, suggesting its potential as a novel therapeutic agent for hyperlipidemia and associated immune decline.

Chrysophanic Acid Suppresses Adipogenesis and Induces Thermogenesis by Activating AMP-Activated Protein Kinase Alpha In vivo and In vitro

Chrysophanic acid (CA) is a member of the anthraquinone family abundant in rhubarb, a widely used herb for obesity treatment in Traditional Korean Medicine. Though several studies have indicated numerous features of CA, no study has yet reported the effect of CA on obesity. In this study, we tried to identify the anti-obesity effects of CA. By using 3T3-L1 adipocytes and primary cultured brown adipocytes as in vitro models, high-fat diet (HFD)-induced obese mice, and zebrafish as in vivo models, we determined the anti-obesity effects of CA. CA reduced weight gain in HFD-induced obese mice. They also decreased lipid accumulation and the expressions of adipogenesis factors including peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in 3T3-L1 adipocytes. In addition, uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α), the brown fat specific thermogenic genes, were up-regulated in brown adipocytes by CA treatment. Furthermore, when co-treated with Compound C, the AMP-activated protein kinase (AMPK) inhibitor, the action of CA on AMPKα was nullified in both types of adipocytes, indicating the multi-controlling effect of CA was partially via the AMPKα pathway. Given all together, these results indicate that CA can ameliorate obesity by controlling the adipogenic and thermogenic pathway at the same time. On these bases, we suggest the new potential of CA as an anti-obese pharmacotherapy.

Cinnamomi Cortex (Cinnamomum verum) Suppresses Testosterone-induced Benign Prostatic Hyperplasia by Regulating 5α-reductase

Cinnamomi cortex (dried bark of Cinnamomum verum) is an important drug in Traditional Korean Medicine used to improve blood circulation and Yang Qi. Benign prostatic hyperplasia (BPH) is a common chronic disease in aging men. This study was conducted to determine the effect of Cinnamomi cortex water extract (CC) on BPH. BPH was induced by a pre-4-week daily injection of testosterone propionate (TP). Six weeks of further injection with (a) vehicle, (b) TP, (c) TP + CC, (d) TP + finasteride (Fi) was carried on. As a result, the prostate weight and prostatic index of the CC treatment group were reduced. Histological changes including epithelial thickness and lumen area were recovered as normal by CC treatment. The protein expressions of prostate specific antigen, estrogen receptor α (ERα), androgen receptor (AR), 5α-reductase (5AR), and steroid receptor coactivator 1 were suppressed by treatment of CC. Immunohistochemical assays supported the western blot results, as the expressions of AR and ERα were down-regulated by CC treatment as well. Further in vitro experiments showed CC was able to inhibit proliferation of RWPE-1 cells by suppressing 5AR and AR. These results all together suggest CC as a potential treatment for BPH.

Cell Models and Their Application for Studying Adipogenic Differentiation in Relation to Obesity: A Review

Over the last several years, the increasing prevalence of obesity has favored an intense study of adipose tissue biology and the precise mechanisms involved in adipocyte differentiation and adipogenesis. Adipocyte commitment and differentiation are complex processes, which can be investigated thanks to the development of diverse in vitro cell models and molecular biology techniques that allow for a better understanding of adipogenesis and adipocyte dysfunction associated with obesity. The aim of the present work was to update the different animal and human cell culture models available for studying the in vitro adipogenic differentiation process related to obesity and its co-morbidities. The main characteristics, new protocols, and applications of the cell models used to study the adipogenesis in the last five years have been extensively revised. Moreover, we depict co-cultures and three-dimensional cultures, given their utility to understand the connections between adipocytes and their surrounding cells in adipose tissue.

Lipin1-Mediated Repression of Adipogenesis by Rutin

Rutin, also called rutoside or quercetin-3-O-rutinoside and sophorin, is a glycoside between the flavonol quercetin and the disaccharide rutinose. Although many effects of rutin have been reported in vitro and in vivo, the anti-adipogenic effects of rutin have not been fully reported. The aim of this study was to confirm how rutin regulates adipocyte related factors. In this study, rutin decreased the expressions of adipogenesis-related genes, including peroxisome proliferators, activated receptor [Formula: see text] (PPAR[Formula: see text], CCAAT/enhancer-binding protein [Formula: see text] (C/EBP[Formula: see text], fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase in 3T3-L1 cells. Rutin also repressed the expression of lipin1, which is an upstream regulator that controls PPAR[Formula: see text] and C/EBP[Formula: see text]. In addition, when 3T3-L1 was transfected with lipin1 siRNA to block lipin1 function, rutin did not affect the expressions of PPAR[Formula: see text] and C/EBP[Formula: see text]. These results suggest that rutin has an anti-adipogenic effect that acts through the suppression of lipin1, as well as PPAR[Formula: see text] and C/EBP[Formula: see text].

Veratri Nigri Rhizoma et Radix (Veratrum nigrum L.) and Its Constituent Jervine Prevent Adipogenesis via Activation of the LKB1-AMPKα-ACC Axis In Vivo and In Vitro

This study was performed in order to investigate the antiobese effects of the ethanolic extract of Veratri Nigri Rhizoma et Radix (VN), a herb with limited usage, due to its toxicology. An HPLC analysis identified jervine as a constituent of VN. By an Oil Red O assay and a Real-Time RT-PCR assay, VN showed higher antiadipogenic effects than jervine. In high-fat diet- (HFD-) induced obese C57BL/6J mice, VN administration suppressed body weight gain. The levels of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT-enhancer-binding protein alpha (C/EBPα), adipocyte fatty-acid-binding protein (aP2), adiponectin, resistin, and LIPIN1 were suppressed by VN, while SIRT1 was upregulated. Furthermore, VN activated phosphorylation of the liver kinase B1- (LKB1-) AMP-activated protein kinase alpha- (AMPKα-) acetyl CoA carboxylase (ACC) axis. Further investigation of cotreatment of VN with the AMPK agonist AICAR or AMPK inhibitor Compound C showed that VN can activate the phosphorylation of AMPKα in compensation to the inhibition of Compound C. In conclusion, VN shows antiobesity effects in HFD-induced obese C57BL/6J mice. In 3T3-L1 adipocytes, VN has antiadipogenic features, which is due to activating the LKB1-AMPKα-ACC axis. These results suggest that VN has a potential benefit in preventing obesity.

Antiobesity Effects of Unripe Rubus coreanus Miquel and Its Constituents: An In Vitro and In Vivo Characterization of the Underlying Mechanism

Background. The objective of the present study was to perform a bioguided fractionation of unripe Rubus coreanus Miquel (uRC) and evaluate the lipid accumulation system involvement in its antiobesity activity as well as study the uRC mechanism of action. Results. After the fractionation, the BuOH fraction of uRC (uRCB) was the most active fraction, suppressing the differentiation of 3T3-L1 adipocytes in a dose-dependent manner. Moreover, after an oral administration for 8 weeks in HFD-induced obese mice, uRCB (10 and 50 mg/kg/day) produced a significant decrease in body weight, food efficiency ratio, adipose tissue weight and LDL-cholesterol, serum glucose, TC, and TG levels. Similarly, uRCB significantly suppressed the elevated mRNA levels of PPARγ in the adipose tissue in vivo. Next, we investigated the antiobesity effects of ellagic acid, erycibelline, 5-hydroxy-2-pyridinemethanol, m-hydroxyphenylglycine, and 4-hydroxycoumarin isolated from uRCB. Without affecting cell viability, five bioactive compounds decreased the lipid accumulation in the 3T3-L1 cells and the mRNA expression levels of key adipogenic genes such as PPARγ, C/EBPα, SREBP-1c, ACC, and FAS. Conclusion. These results suggest that uRC and its five bioactive compounds may be a useful therapeutic agent for body weight control by downregulating adipogenesis and lipogenesis.

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

Arctii Fructus prevents the development of obesity through the regulation of white/brown adipocytes.

Platycodon grandiflorum A. De Candolle Ethanolic Extract Inhibits Adipogenic Regulators in 3T3-L1 Cells and Induces Mitochondrial Biogenesis in Primary Brown Preadipocytes

This study was designed to evaluate the effects of Platycodon grandiflorum A. DC. ethanolic extract (PG) on obesity in brown/white preadipocytes. The effect of PG on the differentiation and mitochondrial biogenesis of brown adipocytes is still not examined. An in vivo study showed that PG induced weight loss in mice with high-fat-diet-induced obesity. PG successfully suppressed the differentiation of 3T3-L1 cells by down-regulating cellular induction of the peroxisome proliferators activated receptor γ (PPARγ), CCAAT enhancer binding protein α (C/EBPα), lipin-1, and adiponectin but increasing expression of silent mating type information regulation 2 homologue 1 (SIRT1) and the phosphorylation of AMP-activated protein kinase α (AMPKα). The effect of PG on the adipogenic factors was compared with that of its bioactive compound platycodin D. In addition, PG increased expressions of mitochondria-related genes, including uncoupling protein 1 (UCP1), peroxisome proliferator activated receptor-coactivator 1 α (PGC1α), PR domain containing 16 (PRDM16), SIRT3, nuclear respiratory factor (NRF), and cytochrome C (CytC) in primary brown adipocytes. These results indicate that PG stimulates the differentiation of brown adipocytes through modulation of mitochondria-related genes and could offer clinical benefits as a supplement to treat obesity.