Liquiritigenin Inhibits Lipid Accumulation in 3T3-L1 Cells via mTOR-Mediated Regulation of the Autophagy Mechanism

β-Elemene inhibits adipogenesis in 3T3-L1 cells by regulating AMPK pathway

The prevalence of childhood obesity in global is quickly augmented, resulting into grievous public health problems and influencing adolescent development. β-Elemene is a sesquiterpene, and can extracted from traditional Chinese medicine-Curcuma longa L. β-Elemene has been discovered to display regulatory functions in multiple diseases, but it's roles in obesity need further investigations. The purpose of this work is to investigate the regulatory impacts of β-elemene on obesity progression and associated pathways. In this study, it was revealed that the heightened lipid accumulation in 3T3-L1 cells triggered by 3-isobutyl-1-methylxanthine + dexamethazone + insulin (MDI) can be restrained by β-elemene. Furthermore, β-elemene can modulate lipid metabolism in 3T3-L1 cells mediated by MDI. The glucose consumption was descended after insulin resistance treatment, but this impact was reversed after β-elemene treatment. At last, it was illustrated that the AMPK pathway was retarded after β-elemene induction, but this change was offset after β-elemene treatment. To sum up, our results manifested that β-elemene inhibited adipogenesis in 3T3-L1 cells, and evoked the AMPK pathway. This project may supply serviceable insights of β-elemene in the progression of obesity.

Caragana jubata ethanol extract ameliorates the symptoms of STZ-HFD-induced T2DM mice by PKC/GLUT4 pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Caragana jubata (Pall.) Poir., a traditional Tibetan medicinal plant in China, is renowned in Tibetan medicine for its hypoglycemic properties and long-standing use in treating diabetes. Despite its extensive clinical use, the mechanisms underlying its blood sugar-lowering effects still need to be explored. Our investigation contributes a new understanding of the hypoglycemic mechanism of C. jubata, validating its traditional medicinal application by demonstrating its ability to increase GLUT4 expression and glucose uptake, crucial elements in treating type 2 diabetes mellitus (T2DM).

AIM OF THE STUDY

This study investigated the potential anti-diabetic effects of C. jubata ethanol extract (CJEE) by upregulating GLUT4 expression and promoting its integration into the plasma membrane in L6 skeletal muscle cells and diabetic mice. Additionally, the research aimed to uncover the mechanisms involved, particularly focusing on the involvement of the PKC signaling pathway and Ca2⁺ release.

MATERIALS AND METHODS

The chemical composition of CJEE was evaluated using UPLC-Q-TOF/MS. Glucose uptake, GLUT4 expression, and plasma membrane fusion in L6 cells were assessed through a glucose oxidase kit, Western blotting, and laser confocal microscopy, respectively. The modulation of GLUT4 by Akt, AMPK, and PKC signaling pathways was investigated utilizing specific inhibitors. The impact of CJEE on intracellular Ca2⁺ concentration was determined with Fluo-4 dye. Additionally, an in vivo study was conducted on high-fat diet (HFD) and streptozotocin (STZ)-induced type 2 diabetic mice to evaluate the effects of CJEE on blood glucose levels, insulin resistance, lipid metabolism, and pancreatic function.

RESULTS

Chemical analysis of CJEE revealed 18 major constituents, primarily flavonoids. In L6 cells, CJEE was found to significantly enhance glucose uptake, increase GLUT4 expression, and facilitate its fusion with the plasma membrane. The study illustrated that CJEE predominantly activates the PKC pathway, with minimal involvement of the Akt pathway, emphasizing the critical role of Ca2⁺ release in GLUT4 regulation. Diabetic mice treated with CJEE exhibited decreased fasting blood glucose levels, enhanced oral glucose tolerance, reduced insulin resistance, and ameliorated lipid metabolism disorders. Additionally, CJEE elevated GLUT4 expression in insulin-sensitive tissues and alleviated pancreatic and hepatic lesions.

CONCLUSIONS

Our results demonstrated that the activation of the PKC pathway and release of Ca2⁺ by CJEE induce GLUT4 expression, promoting its fusion with the plasma membrane. Consequently, this process boosts glucose uptake and enhances insulin sensitivity, underscoring CJEE as a promising option for managing T2DM.

Gan-Jiang-Ling-Zhu decoction improves steatohepatitis induced by choline-deficient-high-fat-diet through the METTL14/N6-methyladenosine-mediated Ugt2a3 expression

ETHNOPHARMACOLOGICAL RELEVANCE

Gan-Jiang-Ling-Zhu (GJLZ) decoction, a classical Chinese herbal prescription, can be applied for the treatment of metabolic diseases including liver steatosis. Although GJLZ decoction has been widely applied clinically for thousands of years, the mechanism of GJLZ decoction behind treatment of nonalcoholic steatohepatitis (NASH) remains relatively unelucidated.

AIM OF THE STUDY

To elucidate the efficacy of GJLZ decoction in the treatment of NASH and to investigate its underlying mechanisms from an epigenetic perspective.

MATERIALS AND METHODS

The quality control of chemical components in GJLZ decoction was conducted. C57BL/6J mice with NASH were induced by feeding them a choline-deficient-high-fat-diet (CDHFD), along with GJLZ decoction intervention for 4 weeks. Then NASH phenotypes including histological steatosis, inflammation, hepatic apoptosis, fibrosis, serum liver enzyme and lipid level were measured. N6-methyladenosine (m6A) and transcriptome sequencing were performed. Levels and functions of methyltransferases and different genes were performed by quantitative polymerase chain reaction, immunofluorescence, gene knockdown, oil red O staining and western blotting.

RESULTS

GJLZ decoction significantly reduced liver weight, liver index and improved hepatic steatosis, and inflammation, as well as inhibited hepatic apoptosis and fibrosis. Moreover, GJLZ decoction significantly reduced the levels of lactate dehydrogenase, aminotransferase, triglyceride, aspartate aminotransferase, and inhibited levels of interleukin 6 and tumor necrosis factor α. Transcriptome and m6A sequencing revealed the landscape of transcriptome and m6A modification influenced by NASH and the following GJLZ decoction intervention. Eleven differential genes were identified, and GJLZ markedly promoted m6A level of UDP glucuronosyltransferase family 2 member A3 (Ugt2a3), to promote its expression. Additionally, GJLZ significantly promoted methyltransferase 14 (METTL14) expression, whereas METTL14 knockdown aggravated hepatocellular steatosis. Finally, METTL14 knockdown significantly reduced the level of Ugt2a3 by promoting its degradation, whereas, Ugt2a3 overexpression could markedly inhibit hepatocellular steatosis.

CONCLUSIONS

GJLZ decoction demonstrates potential in alleviating CDHFD-induced NASH by modulating the METTL14-m6A-Ugt2a3 axis, offering a novel therapeutic approach for NASH treatment.

A narrative review on the mechanism of natural flavonoids in improving glucolipid metabolism disorders

Glucolipid metabolism disorder (GLMD) is a complex chronic disease characterized by glucose and lipid metabolism disorders with a complex and diverse etiology and rapidly increasing incidence. Many studies have identified the role of flavonoids in ameliorating GLMD, with mechanisms related to peroxisome proliferator-activated receptors, nuclear factor kappa-B, AMP-activated protein kinase, nuclear factor (erythroid-derived 2)-like 2, glucose transporter type 4, and phosphatidylinositol-3-kinase/protein kinase B pathway. However, a comprehensive summary of the flavonoid effects on GLMD is lacking. This study reviewed the roles and mechanisms of natural flavonoids with different structures in the treatment of GLMD reported globally in the past 5 years and provides a reference for developing flavonoids as drugs for treating GLMD.

Targeting autophagy drug discovery: Targets, indications and development trends

Autophagy plays a vital role in sustaining cellular homeostasis and its alterations have been implicated in the etiology of many diseases. Drugs development targeting autophagy began decades ago and hundreds of agents were developed, some of which are licensed for the clinical usage. However, no existing intervention specifically aimed at modulating autophagy is available. The obstacles that prevent drug developments come from the complexity of the actual impact of autophagy regulators in disease scenarios. With the development and application of new technologies, several promising categories of compounds for autophagy-based therapy have emerged in recent years. In this paper, the autophagy-targeted drugs based on their targets at various hierarchical sites of the autophagic signaling network, e.g., the upstream and downstream of the autophagosome and the autophagic components with enzyme activities are reviewed and analyzed respectively, with special attention paid to those at preclinical or clinical trials. The drugs tailored to specific autophagy alone and combination with drugs/adjuvant therapies widely used in clinical for various diseases treatments are also emphasized. The emerging drug design and development targeting selective autophagy receptors (SARs) and their related proteins, which would be expected to arrest or reverse the progression of disease in various cancers, inflammation, neurodegeneration, and metabolic disorders, are critically reviewed. And the challenges and perspective in clinically developing autophagy-targeted drugs and possible combinations with other medicine are considered in the review.

Liquiritigenin Confers Liver Protection by Enhancing NRF2 Signaling through Both Canonical and Non-canonical Signaling Pathways

Oxidative stress plays a critical role in drug-induced liver injury. In recent years, liquiritigenin (LQ), a natural flavonoid distributed in Glycyrrhizae Radix et Rhizoma (Gan Cao), shows protective effects against oxidative hepatotoxicity. However, the underlying mechanism remains unclear. In this study, we mainly investigated the role of NRF2, a core transcription factor in oxidative stress, in LQ-induced hepatoprotection. Our results indicated that the function of LQ to eliminate reactive oxygen species in liver cells was dependent on NRF2 activation. Both a canonical signaling pathway and a non-canonical signaling pathway are involved in LQ-induced NRF2 activation. LQ induced NRF2 activation in a KEAP1-C151-dependent manner partially. Meanwhile, LQ led to the blockage of autophagic flux and upregulation of p62, which competitively bound with KEAP1 and conferred NRF2 activation in a KEAP1-C151-independent manner. Totally, our study reveals a novel molecular mechanism underlying the hepatoprotection of LQ, providing a new insight into the pathogenesis and therapeutic strategy of oxidative liver injury.

UPLC-QTOF-MS with a chemical profiling approach for holistic quality evaluation between a material reference of Wen Dan decoction and its commercial preparations

BACKGROUND

Wen Dan decoction (WDD) has been a famous classic formula for resolving phlegm since ancient times in China. Currently, there are many types of WDD commercial preparations produced through modern technology. However, it is not known whether the holistic quality of WDD commercial preparations is consistent with the traditional decocting method to exert its proper effects. Therefore, the WDD material reference was studied and prepared, which can represent the traditional Chinese formulation WDD.

METHODS

A method based on UPLC-QTOF-MS was developed to evaluate the quality of WDD material reference and commercial prescriptions. At the same time, the multivariate statistical method was used to compare the differences between the material reference and the commercial prescription by principal component analysis (PCA) and heatmap. Finally, the UPLC-QTOF-MS method was established to quantitatively study 11 representative components, including naringin, hesperidin, neohesperidin, liquiritin, glycyrrhizic acid, adenosine, liquiritigenin, tangeretin, eriocitrin, naringenin and synephrine.

RESULTS

A total of 107 compounds were identified in the WDD material reference by comparing the retention time and fragment ion characteristics, including 54 flavonoids, 14 triterpenes, 10 organic acids, 7 alkaloids, 7 coumarins and 15 other components. The samples were almost evenly split into two groups, indicating a difference in quality between the WDD material reference and its commercial preparations in multivariate statistical analysis. Eleven major components of linearity, precision, repeatability, stability and recovery rate met the requirements, which were clearly different in commercial preparations and WDD material references. In terms of the content of 11 components in the commercial preparation, only CP8 is close to the material reference, which is in agreement with the statistical analysis of the heatmap. The concentrations of naringin and neohesperidin from the WDD material reference were higher than those from the commercial preparations.

CONCLUSIONS

The quality evaluation method established in this study can be used to identify different sources of WDD but also proves that the WDD material reference contains higher naringin. Furthermore, this study confirmed that the preparation technology of WDD commercial prescriptions should be optimized on the basis of WDD material references, producing the closest possible clinical basis for the substance.

The Perspectives of Plant Natural Products for Mitigation of Obesity

Obesity is a metabolic disease caused by an imbalance between energy intake and consumption, which leads to excessive fat accumulation in adipose tissues [...].