Gomisin N from Schisandra chinensis Ameliorates Lipid Accumulation and Induces a Brown Fat-Like Phenotype through AMP-Activated Protein Kinase in 3T3-L1 Adipocytes

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.

Physiological and Transcriptome Analysis Reveal the Regulation Mechanism Underlying the Muscle Quality Effect of Dietary Schisandra chinensis in Triploid Crucian Carp (Carassius auratus)

Schisandra chinensis (sc) is generally demonstrated to improve antioxidant and immune functions in mammal. The present study through physiological and transcriptome analysis revealed alterations in muscle metabolisms of triploid crucian carp (Carassius auratus) cultured at different concentrations of S. chinensis diets (sc0, sc0.125%, sc0.25%, sc0.5%, sc1%, sc2%) after 8 weeks. The serum antioxidant enzyme activities analysis showed that dietary S. chinensis could reduce oxidative stress and increase organismic antioxidant capacity. Meanwhile, the detected results of muscle components presented that the amino acids and two flavor nucleotides of GMP and IMP significantly elevated while muscle crude lipid significantly reduced in S. chinensis feeding groups. In addition, springiness, chewiness, and fiber density in S. chinensis feeding groups muscle were significantly upregulated while muscle fiber diameter and area showed an opposite trend. By comparative transcriptome analysis of the muscles, functional enrichments of differentially expressed genes showed that multiple terms were related to purine metabolism, glycerolipid metabolism, regulation of actin cytoskeleton, and peroxisome. Finally, some key hub genes such as egln, gst, ggct, su1b, pi3kr4, myh9, lpl, gcdh, mylk, and col4a were identified by weighted gene co-expression network analysis. Taken together, our findings facilitate the understanding of the molecular basis underlying the muscle quality effect of dietary S. chinensis in triploid crucian carp, which provides valuable insights into the nutritional strategies of the aquaculture industry.

Schisandra chinensis-derived gomisin C suppreses lipid accumulation by JAK2-STAT signaling in adipocyte

Gomisin C is a lignan isolated from the fruit of Schisandra chinensis. The current study aimed to investigate the effect of gomisin C on lipid accumulation in adipocytes and its underlying mechanism. Gomisin C effectively inhibited lipid accumulation by downregulating adipogenic factors such as PPARγ and C/EBPα. Gomisin C-mediated suppression of lipid accumulation occurred in the early adipogenic stage; C/EBPβ was downregulated by 55%, while KLF2 was upregulated by 1.5-fold. Gomisin C significantly reduced the production of reactive oxygen species but upregulated antioxidant enzymes, including catalase, SOD1, and Gpx at the mRNA level. Gomisin C regulated NRF2-KEAP1 pathway by increasing NRF2 and decreasing KEAP1, in protein abundance. Furthermore, gomisin C suppressed the JAK2-STAT signaling pathway by decreasing phosphorylation. Taken together, gomisin C reduced early adipogenesis and ROS production by inhibiting the JAK2-STAT signaling pathway but activating the NRF2-KEAP1 signaling pathway.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01263-8.

Naringin promotes fat browning mediated by UCP1 activation via the AMPK signaling pathway in 3T3-L1 adipocytes

Induction of the brown adipocyte-like phenotype in white adipocytes (fat browning) is considered a promising therapeutic strategy to treat obesity. Naringin, a citrus flavonoid, has antioxidant, anti-inflammatory, and anticancer activities. We examined the application of naringin as an anti-obesity compound based on an investigation of its induction of fat browning in 3T3-L1 adipocytes. Naringin did not induce lipid accumulation in differentiated 3T3-L1 adipocytes. Additionally, naringin reduced the expression levels of proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) involved in adipogenesis during lipid metabolism and increased the levels of PPARα and adiponectin involved in fatty acid oxidation. The expression levels of fat browning markers uncoupling protein 1 (UCP1; involved in thermogenesis) and PR domain containing 16 (PRDM16) increased. In addition, naringin treatment resulted in the activation of PPARγ coactivator 1-alpha (PGC-1α), a factor related to UCP1 transcription and mitochondrial biogenesis. Moreover, the expression of beige adipocyte-specific genes such as Cd137, Cited1, Tbx1, and Tmem26 was also induced. The small multi-lipid droplets characteristic of beige adipocytes indicated that naringin treatment increased the levels of all lipolysis markers (hormone-sensitive lipase [HSL], adipose triglyceride lipase [ATGL], perilipin [PLIN], and protein kinase A [PKA]). Adenosine monophosphate-activated protein kinase (AMPK) and UCP1 levels increased by treatment with naringin alone; this was possibly mediated by the stimulation of the AMPK signaling pathway. According to mechanistic studies, naringin activated the thermogenic protein UCP1 via the AMPK signaling pathway. In conclusion, naringin induces fat browning and is a promising therapeutic agent for metabolic disorders based on the regulation of lipid metabolism.

Remodeling of white adipose tissue microenvironment against obesity by phytochemicals

Obesity is a kind of chronic disease due to a long-term imbalance between energy intake and expenditure. In recent years, the number of obese people around the world has soared, and obesity problem should not be underestimated. Obesity is characterized by changes in the adipose microenvironment, mainly manifested as hypertrophy, chronic inflammatory status, hypoxia, and fibrosis, thus contributing to the pathological changes of other tissues. A plethora of phytochemicals have been found to improve adipose microenvironment, thus prevent and resist obesity, providing a new research direction for the treatment of obesity and related diseases. This paper discusses remodeling of the adipose tissue microenvironment as a therapeutic avenue and reviews the progress of phytochemicals in fighting obesity by improving the adipose microenvironment.

Zuogui-Jiangtang-Qinggan-Fang alleviates high-fat diet-induced type 2 diabetes mellitus with non-alcoholic fatty liver disease by modulating gut microbiome-metabolites-short chain fatty acid composition

Non-alcoholic fatty liver disease (NAFLD) pathogenesis is affected by dysbiosis of the gut microbiome and the metabolites it generates. Therefore, restoring the equilibrium between the gut microbiome and the generated metabolites may have therapeutic potential for the syndrome. Zuogui Jiangtang Qinggan Fang (ZGJTQGF) is a Chinese herbal formulation used clinically to treat type 2 diabetic mellitus (T2DM) and fatty liver disease. However, its pharmacological mechanisms have not been well characterized. This work aimed to evaluate the hepatoprotective mechanism of ZGJTQGF in T2DM with NAFLD mice by incorporating gut microbiota, short-chain fatty acids（SCFAs）, and metabolomic analysis, and then to provide strong support for clinical treatment of T2DM with NAFLD. The sequencing of 16 S rRNA revealed that ZGJTQGF therapy modified the composition and abundance of the gut microbiome, raised the level of SCFAs, and restored the intestinal mucosal barrier. The non-targeted metabolomic analysis of liver tissues identified 212 compounds, of which108 were differentially expressed between the HFD and ZGJTQGF groups. Moreover, L-glutamic acid, L-Phenylalanine, Glycine, Taurine, Deoxycholic acid, and citric acid levels were also considerably altered by ZGJTQGF. Our findings suggest that ZGJTQGF ameliorates HFD-induced hepatic steatosis by modulating the gut microbiota composition and its metabolites and boosting the levels of SCFAs. More notably, ZGJTQGF may be a promising medication for preventing and treating NAFLD.

Schisandrin C isolated from Schisandra chinensis fruits inhibits lipid accumulation by regulating adipogenesis and lipolysis through AMPK signaling in 3T3-L1 adipocytes

In this study, lignans of Schisandra chinensis fruits (SCF) were profiled using HPLC-MS/MS, and the inhibitory effects of nine of these lignans were evaluated on triglyceride (TG) accumulation. We then examined the effects and molecular mechanisms on adipogenesis and lipolysis of schisandrin C (SC), which most inhibited TG levels during adipogenesis of 3T3-L1 cells. Treatment of 3T3-L1 cells with SC markedly decreased adipocyte differentiation but did not influence cell proliferation. During adipogenesis, SC significantly reduced total lipid and TG contents and down-regulated the mRNA expressions of C/EBPα, PPARγ, SREBP1c, aP2, and FAS. In addition, SC significantly increased p-AMPK, and this activation regulated the protein levels of major adipogenic transcription factors (PPARγ and C/EBPα). Furthermore, SC lowered the mRNA expressions of HSL and perilipin and inhibited pancreatic lipase levels, which are both related to lipolysis. PRACTICAL APPLICATIONS: Our results indicate that SC regulates lipogenesis and lipolysis by increasing AMPK phosphorylation and suggest that it may be beneficial for preventing obesity and related metabolic diseases. Thus, this study proposes a mechanical basis for developing SC-containing foods as a beneficial dietary strategy.

Pancreatic lipase and alpha-glucosidase inhibitors screening from Schisandra chinensis based on spectrum-effect relationship and ultra-high-performance liquid chromatography-tandem mass spectrometry

As a traditional Chinese medicine, Schisandra chinensis has a potential weight-loss effect by delaying carbohydrate absorption and improving lipid metabolic disorders. However, its active components are still unclear and require in-depth research. In this study, the active components of Schisandra chinensis responsible for pancreatic lipase and alpha-glucosidase inhibitory activity were screened and identified based on a spectrum-effect relationship study in combination with ultra-performance liquid chromatography-tandem mass spectrometry analysis. The ultra-high-performance liquid chromatography fingerprints of 17 batches of Schisandra chinensis were established, and 14 common peaks were specified by similarity analysis. The half-maximal inhibition concentration values for pancreatic lipase and alpha-glucosidase inhibition were separately measured by enzymatic reactions. Using multivariate statistical methods including principal component analysis, partial least square analysis, and grey relational analysis, the correlation models between the peak areas of 14 common peaks and half-maximal inhibition concentration values were constructed, and the chromatographic peaks making a great contribution to efficacy were screened out. Peak1, Peak2, Peak4, Peak6, Peak9, Peak10, Peak11, and Peak13 were responsible for alpha-glucosidase inhibitory activity, while Peak1, Peak4, Peak6, Peak9, Peak10, and Peak11 for pancreatic lipase inhibitory activity. Finally, the 70% ethanol extracts of Schisandra chinensis were characterized by ultra-high-performance liquid chromatography-tandem mass spectrometry analysis, and 14 lignans were identified to further elucidate the active constituents of Schisandra chinensis. The positive results suggested the proposed strategy is simple and effective to screen active components from complex medicinal plants.

In vitro and ex vivo models of adipocytes

Adipocytes are specialized cells with pleiotropic roles in physiology and pathology. Several types of fat cells with distinct metabolic properties coexist in various anatomically defined fat depots in mammals. White, beige, and brown adipocytes differ in their handling of lipids and thermogenic capacity, promoting differences in size and morphology. Moreover, adipocytes release lipids and proteins with paracrine and endocrine functions. The intrinsic properties of adipocytes pose specific challenges in culture. Mature adipocytes float in suspension culture due to high triacylglycerol content and are fragile. Moreover, a fully differentiated state, notably acquirement of the unilocular lipid droplet of white adipocyte, has so far not been reached in two-dimensional culture. Cultures of mouse and human-differentiated preadipocyte cell lines and primary cells have been established to mimic white, beige, and brown adipocytes. Here, we survey various models of differentiated preadipocyte cells and primary mature adipocyte survival describing main characteristics, culture conditions, advantages, and limitations. An important development is the advent of three-dimensional culture, notably of adipose spheroids that recapitulate in vivo adipocyte function and morphology in fat depots. Challenges for the future include isolation and culture of adipose-derived stem cells from different anatomic location in animal models and humans differing in sex, age, fat mass, and pathophysiological conditions. Further understanding of fat cell physiology and dysfunction will be achieved through genetic manipulation, notably CRISPR-mediated gene editing. Capturing adipocyte heterogeneity at the single-cell level within a single fat depot will be key to understanding diversities in cardiometabolic parameters among lean and obese individuals.