Insulin-resistant HepG2 Cells Research Articles

MicroRNAs Dependent G-ELNs Based Intervention Improves Glucose and Fatty Acid Metabolism While Protecting Pancreatic β-Cells in Type 2 Diabetic Mice.

Metabolic disorders such as Type 2 diabetes mellitus (T2DM) imposes a significant global health burden. Plant-derived exosome like nanoparticles (P-ELNs) have emerged as a promising therapeutic alternate for various diseases. Present data demonstrates that treatment with Ginger-derived exosome like nanoparticles (G-ELNs) enhance insulin dependent glucose uptake, downregulate gluconeogenesis and oxidative stress in insulin resistant HepG2 cells. Furthermore, oral administration of G-ELNs in T2DM mice decreases fasting blood glucose levels and improves glucose tolerance as effectively as metformin. These improvements are attributed to the enhanced phosphorylation of Protein kinase B (Akt-2), the phosphatidylinositol 3-kinase at serine 474 which consequently leads to increase in hepatic insulin sensitivity, improvement in glucose homeostasis and decrease in ectopic fat deposition. Oral administration of G-ELNs also exerts protective effect on Streptozotocin (STZ)-induced pancreatic β-cells damage, contributing to systemic amelioration of T2DM. Further, as per computational tools, miRNAs present in G-ELNs modulate the phosphatidylinositol 3-kinase (PI3K)/Akt-2pathway and exhibit strong interactions with various target mRNAs responsible for hepatic gluconeogenesis, ectopic fat deposition and oxidative stress. Furthermore, synthetic mimic of G-ELNs miRNA effectively downregulates its target mRNA in insulin resistant HepG2 cells. Overall, the results indicate that the miRNAs present in G-ELNs target hepatic metabolism thus, exerting therapeutic effects in T2DM.

Flavonoids from Ougan (Citrus suavissima Hort. ex Tanaka) peel exert hypoglycemic potency through inhibiting insulin resistance in HepG2 cells and regulating gut microbiota in diabetic mice

To fully and value-addedly utilize the citrus peel resource, flavonoids were extracted and purified from peel powder of Ougan (Citrus suavissima Hort. ex Tanaka) using an ultrasonic assisted ethanol solution extraction method and AB-8 macroporous resin purification. The obtained flavonoid extract from peel of Ougan (FEPO) was used for the hypoglycemic experiments in vitro and in vivo on glucose consumption in insulin resistance model HepG2 cells and streptozotocin induced diabetes model mice. A significant reduction of glucose consumption in the model cells while a significant increase in the treated were found in a dose-dependent manner, compared to 5.2241 ± 0.2201 mmol/L of the normal cells (P < 0.05). When the FEPO concentration was 80 μg/mL, the cell glucose consumption was 4.4055 ± 0.1772 mmol/L. Compared with those in the model group (diabetic mice), the fasting blood glucose in the FEPO intervened mice was significantly decreased (P < 0.05). FEPO intervention caused decreased levels of TC, TG, LDL-C, and increased HDL-C and insulin contents in the serums as well as ameliorative histopathology of the liver, kidney, and pancreas in diabetic mice. FEPO improved the gut microbiota structure of diabetic mouse by regulating its composition, especially significantly increasing the relative abundance of Lactobacillus, Ileibacterium, unclassified_f_Lachnospiracea, Romboutsia, norank_f_Muribaculaceae, Faecalibaculum and Coriobacteriaceae_UCG-002 (P < 0.05), while decreasing that of norank_f_norank_o_Clostridia_UCG-014, Lachnospiraceae_NK4A136_group and Candidatus_Saccharimonas. In conclusion, FEPO had good hypoglycemic efficacies both in vitro and in vivo as well as gut microbiota regulating effect.

Multi-layered proteomics identifies insulin-induced upregulation of the EphA2 receptor via the ERK pathway which is dependent on low IGF1R level

Insulin resistance impairs the cellular insulin response, and often precedes metabolic disorders, like type 2 diabetes, impacting an increasing number of people globally. Understanding the molecular mechanisms in hepatic insulin resistance is essential for early preventive treatments. To elucidate changes in insulin signal transduction associated with hepatocellular resistance, we employed a multi-layered mass spectrometry-based proteomics approach focused on insulin receptor (IR) signaling at the interactome, phosphoproteome, and proteome levels in a long-term hyperinsulinemia-induced insulin-resistant HepG2 cell line with a knockout of the insulin-like growth factor 1 receptor (IGF1R KO). The analysis revealed insulin-stimulated recruitment of the PI3K complex in both insulin-sensitive and -resistant cells. Phosphoproteomics showed attenuated signaling via the metabolic PI3K-AKT pathway but sustained extracellular signal-regulated kinase (ERK) activity in insulin-resistant cells. At the proteome level, the ephrin type-A receptor 2 (EphA2) showed an insulin-induced increase in expression, which occurred through the ERK signaling pathway and was concordantly independent of insulin resistance. Induction of EphA2 by insulin was confirmed in additional cell lines and observed uniquely in cells with high IR-to-IGF1R ratio. The multi-layered proteomics dataset provided insights into insulin signaling, serving as a resource to generate and test hypotheses, leading to an improved understanding of insulin resistance.

Linarin Identified as a Bioactive Compound of Lycii Cortex Ameliorates Insulin Resistance and Inflammation Through the c-FOS/ARG2 Signaling Axis.

Insulin resistance (IR) is a central pathophysiological process underlying numerous chronic metabolic disorders, including type 2 diabetes and obesity. Lycii Cortex, a widely used traditional Chinese herb, has demonstrated potential benefits in preventing and managing diabetes and IR. Whereas, the specific bioactive compounds responsible for these protective effects and their underlying mechanisms of action remain elusive. This study aimed to identify the bioactive components within Lycii Cortex that contribute to its anti-diabetic effects and to elucidate the molecular mechanisms underlying its beneficial actions on insulin resistance. Network pharmacology and molecular docking analyses were employed to identify the potential active compounds in Lycii Cortex and their corresponding target proteins. An invitro model of IR was established using palmitic acid (PA)-treated HepG2 cells. Cell viability was assessed using the CCK-8 assay, while glucose uptake was evaluated by 2-NBDG staining and extracellular glucose measurement. To validate the invitro findings, an invivo model of obesity-induced IR was established using high-fat diet (HFD)-fed mice. The network pharmacology analysis preliminarily identified 13 candidate chemicals and 10 hub LyC and IR-related genes (LIRRGs). Molecular docking analysis demonstrates that Linarin as the potential active component exhibits the greatest potential to target c-FOS for preventing obesity-induced IR. Enrichment analysis suggested that Linarin-targeted pathways are correlated with inflammation. Invitro experimental validation demonstrated that Linarin was capable of protecting against PA-induced IR in HepG2 cells evidenced by improving glucose uptake ability and reducing extracellular glucose content. Additionally, we found that Linarin ablated PA-induced increase in the expression of c-FOS and inflammatory cytokines. Furthermore, in PA-treated cells, silencing c-FOS markedly improved glucose consumption, and reduced inflammation and Arginase 2 (ARG2) expression. Similarly, as exposure to PA, silencing ARG2 also ameliorated glucose uptake and inflammation, while not affecting c-FOS expression. Invivo experiments further showed that Linarin administration remarkably improved glucose tolerance and insulin sensitivity, and reduced the fat mass and body weight in HFD-induced obese mice. In this study, Linarin has been identified as the bioactive compound of Lycii Cortex to ameliorate obesity-related IR and inflammation through the c-FOS/ARG2 signaling cascade. These findings underscore the therapeutic potential of Linarin and provide valuable insights into developing novel intervention strategies for type 2 diabetes therapy.

Composition of four polyphenol fractions extracted from partridge tea and their mechanisms on ameliorate insulin resistance in HepG2 cells

Partridge tea is a plant used as a speciality tea drink in Hainan Province, China. The aim of this study was to isolate polyphenols from partridge tea, investigate their main constituent compositions and ameliorative effects on insulin resistance in insulin resistant HepG2 (IR-HepG2) cells. PTP was obtained from partridge tea, then PTP-1, PTP-2 and PTP-3 were obtained after further purification. The polyphenol contents of PTP, PTP-1, PTP-2, PTP-3 were determined to be 15.9%, 51.4%, 42.51% and 22.74%, respectively. PTP and PTP-1 had similar compositions, and the contents of the main components of PTP-1 was higher than that of PTP. Structural compositions and contents of PTP-2 and PTP-3 differ significantly. Further analysis indicated that PTP failed to have significant hypoglycaemic activity, while other three polyphenols regulated the fat metabolism disorders caused by insulin resistance, thus improving the body’s utilization of blood glucose. In addition, the three polyphenols reversed the damage caused by insulin resistance in IR-HepG2 cells by up-regulating the activities of HK (200 μg/mL PTP-1: 2.8414 mol/min/mL) and PK (200 μg/mL PTP-1: 10.7204 U/L), increasing the activity of SOD and CAT and decreasing the level of MDA. The mRNA results showed that PTP-1, PTP-2 and PTP-3 could achieve hypoglycaemic efficacy in the body by regulating the IRS-1/PI3K/AKT signal pathway. In summary, our results suggested that the polyphenols of partridge tea could be a promising natural source for preventing and treating hyperglycemia.

Herbacetin Inhibits Human Fructose 1,6-Bisphosphatase Among a Panel of Chromone Derivatives and Pyrazoles, Demonstrating Positive Effects on Insulin-Resistant HepG2 Cells.

In patients with type 2 diabetes mellitus (DM), excessive gluconeogenesis is considered a major contributor to hyperglycemia. Therefore, targeting fructose 1,6-bisphosphatase (FBPase), a key regulatory enzyme involved in gluconeogenesis, has gained interest as a potential therapeutic target for managing DM. In this study, a library of 42 structurally-related chromone derivatives (including flavonoids, 2-styrylchromones, and 2-(4-arylbuta-1,3-dien-1-yl)chromones, named as 2-styrylchromone-related derivatives), as well as 4- and 5-styrylpyrazoles, were tested against human FBPase using a noncellular microanalysis screening system. Herbacetin, 3,4',5,7,8-pentahydroxyflavone, inhibited FBPase activity with an IC50 value of 6.4 ± 0.7 μM. The effects of herbacetin were also explored using an insulin-resistant human hepatocellular carcinoma cell line (HepG2 cells). The results showed that herbacetin significantly decrease insulin resistance by promoting the phosphorylation of protein kinase B (Akt), and exhibited a capacity to ameliorate inflammation, evidenced by the modulation of the inhibitor of κB alpha (IκBα). This study provides important considerations for the design of novel FBPase inhibitors. Furthermore, it indicates a preliminary potential of herbacetin's dual action in improving insulin resistance and decreasing inflammation, suggesting the need for further investigation of this compound for addressing the complexities of type 2 DM management.

Comparison of polysaccharides from stem barks and flowers of Magnolia officinalis: Compositional characterization, hypoglycemic and photoprotection activities.

The extraction of polysaccharides from stem barks and flowers of Magnolia officinalis were optimized using response surface methodology and the maximum yields were 4.12 ± 0.06 % and 5.5 ± 0.08 %, respectively. Three homogeneous polysaccharides including MOBP-I, MOBP-II and MOFP-I were further purified and their compositional characterization were compared. Molecular weights of MOBP-I, MOBP-II and MOFP-I were 5.9 × 103, 6.8 × 103 and 3.9 × 104 Da, respectively. Gas chromatography (GC) analysis suggested that MOBP-I, MOBP-II and MOFP-I were composed of rhamnose, arabinose, mannose, glucose and galactose at different ratios and exhibited different appearance and glycosidic linkages. MOFP-I but not MOBP-I and MOBP-II had three helix structures. MOBP-I, MOBP-II and MOFP-I showed significant hypoglycemic and photoprotection capacities with different efficacy. MOBP-I had greater hypoglycemic activity, as evidenced by the increased α-glucosidase inhibition activity and glucose consumption in insulin-resistant HepG2 cells. MOBP-II and MOFP-I were more powerful in reversing ultraviolet-B (UVB)-irradiated photoaging of HaCaT cells. The difference of polysaccharides compositions might explain for their bioactivity discrepancy.

VEGFB ameliorates insulin resistance in NAFLD via the PI3K/AKT signal pathway

BackgroundNon-alcoholic fatty liver disease (NAFLD) is one of the most universal liver diseases with complicated pathogenesis throughout the world. Insulin resistance is a leading risk factor that contributes to the development of NAFLD. Vascular endothelial growth factor B (VEGFB) was described by researchers as contributing to regulating lipid metabolic disorders. Here, we investigated VEGFB as a main target to regulate insulin resistance and metabolic syndrome.MethodsIn this study, bioinformatics, transcriptomics, morphological experiments, and molecular biology were used to explore the role of VEGFB in regulating insulin resistance in NAFLD and its molecular mechanism based on human samples, animal models, and cell models. RNA-seq was performed to analyze the signal pathways associated with VEGFB and NAFLD; Palmitic acid and High-fat diet were used to induce insulin-resistant HepG2 cells model and NAFLD animal model. Intracellular glucolipid contents, glucose uptake, hepatic and serum glucose and lipid levels were examined by Microassay and Elisa. Hematoxylin-eosin staining, Oil Red O staining, and Periodic acid-schiff staining were used to analyze the hepatic steatosis, lipid droplet, and glycogen content in the liver. Western blot and quantitative real-time fluorescent PCR were used to verify the expression levels of the VEGFB and insulin resistance-related signals PI3K/AKT pathway.ResultsWe observed that VEGFB is genetically associated with NAFLD and the PI3K/AKT signal pathway. After VEGFB knockout, glucolipids levels were increased, and glucose uptake ability was decreased in insulin-resistant HepG2 cells. Meanwhile, body weight, blood glucose, blood lipids, and hepatic glucose of NAFLD mice were increased, and hepatic glycogen, glucose tolerance, and insulin sensitivity were decreased. Moreover, VEGFB overexpression reduced glucolipids and insulin resistance levels in HepG2 cells. Specifically, VEGFB/VEGFR1 activates the PI3K/AKT signals by activating p-IRS1Ser307 expression, inhibiting p-FOXO1pS256 and p-GSK3Ser9 expressions to reduce gluconeogenesis and glycogen synthesis in the liver. Moreover, VEGFB could also enhance the expression level of GLUT2 to accelerate glucose transport and reduce blood glucose levels, maintaining glucose homeostasis.ConclusionsOur studies suggest that VEGFB could present a novel strategy for treating NAFLD as a positive factor.Graphical

Extraction, in vitro hypoglycaemic activity and active ingredient analysis of polyphenols from walnut green husk

A variety of polyphenols in walnut green husk have shown physiological benefits, but their primary hypoglycemic active ingredients remain unclear. We report the extraction of walnut green husk polyphenols (WGHP) and their hypoglycemic effects in vitro. WGHP was extracted using ultrasound-assisted ethanol extraction, with optimization via response surface methodology resulting in 88.0 ± 0.1 % purity after D101 macroporous resin purification. WGHP effectively inhibited α-glucosidase and α-amylase, with IC50 values of 3.42 μg/mL and 2.56 mg/mL, respectively. It also increased glycogen synthesis in insulin-resistant HepG2 cells and enhanced glucose consumption in 3T3-L1 and insulin-resistant HepG2 cells. Screening six α-glucosidase ligands from WGHP using affinity ultrafiltration and UPLC-MS/MS, combined with molecular docking, identified hydrogen bonds and binding energies between the ligands and the enzyme. These results highlight the hypoglycemic potential of walnut green husk polyphenols and provide a basis for future therapeutic research.

The effect of Helicobacter pylori-derived extracellular vesicles on glucose metabolism and induction of insulin resistance in HepG2 cells.

Helicobacter pylori infection has been associated with the development of insulin resistance (IR). This study aimed to examine the effect of H. pylori-derived extracellular vesicles (EVs) on IR induction. EVs were derived from two H. pylori strains, and characterised by transmission electron microscopy and dynamic light scattering. Different concentrations of insulin were added to HepG2 cells to induce IR model. HepG2 cells were exposed to various concentrations of H. pylori-derived EVs to assess IR development. The gene expression of IRS1, AKT2, GLUT2, IL-6, SOCS3, c-Jun and miR-140 was examined using RT-qPCR. Glucose uptake analysis revealed insulin at 5 × 10 -7 mol/l and EVs at 50 µg/ml induced IR model in HepG2 cells. H. pylori-derived EVs downregulated the expression level of IRS1, AKT2, and GLUT2, and upregulated IL-6, SOCS3, c-Jun, and miR-140 expression in HepG2 cells. In conclusion, our findings propose a novel mechanism by which H. pylori-derived EVs could potentially induce IR.

Berberine Ameliorates High-fat-induced Insulin Resistance in HepG2 Cells by Modulating PPARs Signaling Pathway.

Berberine (BBR), also known as berberine hydrochloride, was isolated from the rhizomes of the Coptis chinensis. Studies have reported that BBR plays an important role in glycolipid metabolism, including insulin (IR). The targets, and molecular mechanisms of BBR against hyperlipid-induced IR is worthy to be further studied. The related targets of BBR were identified via Pharmmapper database and relevant targets of diabetes were obtained through GeneCards and Online Mendelian Inheritance in Man (OMIM) database. The common targets were employed with the STRING database and visualized with the protein-protein interactions (PPI) network. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis was performed to explore the biological progress and pathways. In vitro, human hepatocellular carcinomas (HepG2) cell was used as experimental cell line, and an insulin resistant HepG2 cell model (IR-HepG2) was constructed using free fatty acid induction. After intervention with BBR, glucose consumption and uptake in HepG2 cells were observed. Molecular docking was used to test the interaction between BBR and key targets, and real-time fluorescence quantitative PCR was used to detect the regulatory effect of BBR on related targets. 262 overlapped targets were extracted from BBR and diabetes. In the KEGG enrichment analysis, the peroxisome proliferator activated receptor (PPAR) signaling pathway was included. In vitro experiments, BBR can significantly increase sugar consumption and uptake in IR HepG2 cells, while PPAR inhibitors can weaken the effect of BBR on IR-HepG2. The PPAR signaling pathway is one of the important pathways for BBR to improve high-fat-induced insulin resistance in HepG2 cells.

Anti-Hyperglycemic Effects of Thai Herbal Medicines

This study aims to investigate selected medicinal plants’ anti-oxidative and antihyperglycemic activities to develop an effective remedy for lowering blood glucose levels and/or reducing diabetes complications. Thai medicinal plants, reported to have blood sugar-lowering effects, were selected for the study: Coccinia grandis, Gymnema inodorum, Gynostemma pentaphyllum, Hibiscus sabdariffa, Momordica charantia, Morus alba, and Zingiber officinale. Each species was extracted by Soxhlet’s extraction using ethanol as solvent. The ethanolic crude extract of each species was then evaluated for its phytochemicals, anti-oxidant, and antihyperglycemic activities. The results showed that the extract of Z. officinale gave the highest values of total phenolic and total flavonoid content (167.95 mg gallic acid equivalents (GAE)/g and 81.70 mg CE/g, respectively). Anti-oxidant activity was determined using DPPH and ABTS radical scavenging activity. Among the ethanolic extracts, Z. officinale exhibited the highest anti-oxidant activity with IC50 values of 19.16 and 8.53 µg/mL, respectively. The antihyperglycemic activity was assessed using α-glucosidase inhibitory and glucose consumption activities. M. alba and G. pentaphyllum demonstrated the highest α-glucosidase inhibitory activity among the ethanolic extracts, with IC50 values of 134.40 and 329.97 µg/mL, respectively. Z. officinale and H. sabdariffa showed the highest percentage of glucose consumption activity in induced insulin-resistant HepG2 cells at a concentration of 50 µg/mL with 145.16 and 107.03%, respectively. The results from α-glucosidase inhibitory and glucose consumption activities were developed as an effective antihyperglycemic remedy. Among the remedies tested, the R1 remedy exhibited the highest potential for reducing blood glucose levels, with an IC50 value of 122.10 µg/mL. Therefore, the R1 remedy should be further studied for its effects on animals.

Sangyod Rice Extract Mitigates Insulin Resistance in HepG2 cells and Hepatic Steatosis in Diabetic Rats via AMPK/mTOR/MAPK Signaling Pathways

Sangyod Rice Extract Mitigates Insulin Resistance in HepG2 cells and Hepatic Steatosis in Diabetic Rats via AMPK/mTOR/MAPK Signaling Pathways

Targeting insulin resistance: myricetin and isorhamnetin from Hardwickia binata, and luteolin from Hedysarum alpinum enhance glucose uptake and AMPK signaling in HepG2 cells

This study examined five plants (Xylopia aethiopica, Agave sisalana, Hardwickia binata, Hedysarum alpinum, and Toxicodendron vernicifluum) for their potential to address insulin resistance in type 2 diabetes. In-vitro assays showed that H. binata leaves and H. alpinum flowers inhibited α-glucosidase and α-amylase while enhancing glucose uptake in normal and insulin-resistant HepG2 cells. Phytochemical screening and SPE purification identified the key constituents responsible for the effects. The chromatographic and spectral analysis confirmed flavonoids in H. binata (myricetin, isorhamnetin, quercetin, kaempferol, and catechin) and H. alpinum (luteolin, quercetin, kaempferol, and apigenin). Myricetin, isorhamnetin, and luteolin significantly increased glucose uptake, enhanced hexokinase and pyruvate kinase activities, and promoted IRec and IRS-1 phosphorylation, modulating insulin signalling. They activated AMPK and Akt, with molecular docking confirming strong AMPK binding. These findings suggest that H. binata, H. alpinum, and their flavonoids are promising candidates for managing insulin resistance and type 2 diabetes, warranting further research.

Single-Atom Ce-N-C Nanozyme Ameliorates Type 2 Diabetes Mellitus by Improving Glucose Metabolism Disorders and Reducing Oxidative Stress.

Type 2 diabetes mellitus (T2DM) as a chronic metabolic disease has become a global public health problem. Insulin resistance (IR) is the main pathogenesis of T2DM. Oxidative stress refers to an imbalance between free radical production and the antioxidant system, causing insulin resistance and contributing to the development of T2DM via several molecular mechanisms. Besides, the reduction in hepatic glycogen synthesis also leads to a decrease in peripheral insulin sensitivity. Thus, reducing oxidative stress and promoting glycogen synthesis are both targets for improving insulin resistance and treating T2DM. The current study aims to investigate the pharmacological effects of single-atom Ce-N-C nanozyme (SACe-N-C) on the improvement of insulin resistance and to elucidate its underlying mechanisms using HFD/STZ-induced C57BL/6J mice and insulin-resistant HepG2 cells. The results indicate that SACe-N-C significantly improves hepatic glycogen synthesis and reduces oxidative stress, as well as pancreatic and liver injury. Specifically, compared to the T2DM model group, fasting blood glucose decreased by 29%, hepatic glycogen synthesis increased by 17.13%, and insulin secretion increased by 18.87%. The sod and GPx in the liver increased by 17.80% and 25.28%, respectively. In terms of mechanism, SACe-N-C modulated glycogen synthesis through the PI3K/AKT/GSK3β signaling pathway and activated the Keap1/Nrf2 pathway to alleviate oxidative stress. Collectively, this study suggests that SACe-N-C has the potential to treat T2DM.

Structural characteristics of neutral polysaccharides purified from coix seed and its anti-insulin resistance effects on HepG2 cells.

Coix seed is recognized as a functional medicinal food due to its valuable biological activities, with polysaccharides being the primary active compounds. In this study, an ultrasonic-assisted enzymatic extraction technique was employed, and response surface methodology was used to optimize the yield of polysaccharides to 9.55 ± 0.26%. A novel neutral polysaccharide, CSPsN-1, was purified with a molecular weight of 7.75 kDa. CSPsN-1 was composed of arabinose, galactose, glucose, xylose, and mannose in molar ratios of 0.48: 7.92: 86.39: 2.42: 2.79. Its backbone composed of →4)-α-D-Glcp-(1→ and →3,4)-α-D-Glcp-(1→ units, with terminal residues of α-D-Glcp. Invitro experiments, CSPsN-1 enhanced glucose consumption in insulin-resistant HepG2 cells and upregulated GLUT4 expression by activating the PI3K/AKT signaling pathway. These findings suggest that CSPsN-1 holds significant promise as a functional ingredient for treating insulin resistance and related metabolic disorders.

Epicatechin and β-Glucan from Whole Highland Barley Grain Synergistic Benefit on Attenuating Hyperglycemia via Improving Hepatic Glucose Metabolism in Diabetic C57BL/6J Mice.

Our previous study proved that epicatechin (EC) and β-glucan (BG) from whole-grain highland barley synergistically modulate glucose metabolism in insulin-resistant HepG2 cells. However, the main target and the mechanism underlying the modulation of glucose metabolism in vivo remain largely unknown. In this study, cell transfection assay and microscale thermophoresis analysis revealed that EC and BG could directly bind to the insulin receptor (IR) and mammalian receptor for rapamycin (mTOR), respectively. Molecular dynamic analysis indicated that the key amino acids of binding sites were Asp, Met, Val, Lys, Ser, and Tys. EC supplementation upregulated the IRS-1/PI3K/Akt pathway, while BG upregulated the mTOR/Akt pathway. Notably, supplementation with EC + BG significantly increased Akt and glucose transporter type 4 (GLUT4) protein expressions, while decreasing glycogen synthase kinase 3β (GSK-3β) expression in liver cells as compared to the individual effects of EC and BG, indicating their synergistic effect on improving hepatic glucose uptake and glycogen synthesis. Consistently, supplementation with EC + BG significantly decreased blood glucose levels and improved oral glucose tolerance compared to EC and BG. Therefore, combined supplementation with EC and BG may bind to corresponding receptors, targeting synergistic activation of Akt expression, leading to the improvement of hepatic glucose metabolism and thereby ameliorating hyperglycemia in vivo.

Evaluation of cadmium effects on the glucose metabolism on insulin resistance HepG2 cells

Cadmium (Cd) is an environmental endocrine disruptor. Despite increasing research about the metabolic effects of Cd on HepG2 cells, information about the metabolic effects of Cd on insulin resistance HepG2 (IR-HepG2) cells is limited. Currently, most individuals with diabetes are exposed to Cd due to pollution. Previously, we reported that Cd exposure resulted in decreased blood glucose levels in diabetic mice, the underlying mechanism deserves further study. Therefore, we used palmitic acid (0.25 mM) to treat HepG2 cells to establish IR-HepG2 model. IR-HepG2 cells were exposed to CdCl2 (1 μM and 2 μM). Commercial kits were used to measure glucose production, glucose consumption, ROS and mitochondrial membrane potential. Western blot and qRT-PCR were used to measure the proteins and genes of glucose metabolism. In the current study setting, we found no significant changes in glucose metabolism in Cd-exposed HepG2 cells, but Cd enhanced glucose uptake, inhibited gluconeogenesis and activated the insulin signaling pathway in IR-HepG2 cells. Meanwhile, we observed that Cd caused oxidative stress and increased the intracellular calcium concentration and inhibited mitochondrial membrane potential in IR-HepG2 cells. Cd compensatingly increased glycolysis in IR-HepG2 cells. Collectively, we found Cd ameliorated glucose metabolism disorders in IR-HepG2 cells. Furthermore, Cd exacerbated mitochondrial damage and compensatory increased glycolysis in IR-HepG2 cells. These findings will provide novel insights for Cd exposure in insulin resistant individuals.

Study on Pharmacodynamic Substances and Quality Control of Jiuwei Jiangtang Oral Liquid Based on Network Pharmacology, Fingerprint and In Vitro Experiment

Objective: This study aims to explore the fingerprint and quality control index components of Jiuwei Jiangtang Oral Liquid (JWJT), known for its therapeutic effects on type 2 diabetes mellitus (T2DM). Methods: This study employed network pharmacology and molecular docking to screen the core components, core targets, and pathways of JWJT. Additionally, HPLC fingerprint was established for 12 batches of JWJT. 12 batches of JWJT were evaluated using stoichiometry and common peaks were determined following a similarity assessment. The effective substances were selected to verify the index components of JWJT through assessing their control over glucose consumption in insulin-resistant HepG2 cells and their α-glucosidase inhibitory activity. Results: Through network pharmacology and molecular docking analysis, puerarin, calycosin, ellagic acid, kaempferol-3-O-rutinoside, and kaempferol were identified as core components of JWJT for treating T2DM. Key targets such as AKT1, PIK3R1, INSR, TNF, and EGFR were implicated in regulating pathways including HIF-1, MAPK, and PI3K-Akt in T2DM treatment. The HPLC fingerprints of 12 batches of JWJT samples revealed 10 common peaks, with puerarin, calycosin, ellagic acid, and kaempferol-3-O-rutinoside specifically identified among 4 chromatographic peaks. Using chemical pattern recognition, samples were categorized into two groups, with puerarin, calycosin, and ellagic acid identified as differential markers. Verification through glucose consumption in insulin-resistant HepG2 cells and α-glucosidase inhibitory activity confirmed that puerarin, calycosin, and ellagic acid were active ingredients suitable as quality control indicators for JWJT. Conclusion: The JWJT fingerprint method established in this study is both simple and reproducible. The selected index components will serve as the basis for quality control of JWJT and introduce a novel approach for selecting and verifying quality index components of JWJT in T2DM treatment.

Nine new nor-3,4-seco-dammarane triterpenoids from the leaves of Cyclocarya paliurus and their hypoglycemic activity

This manuscript describes the isolation of nine new nor-3,4-seco-dammarane triterpenoids, norqingqianliusus A-I (1–9) and one known nortriterpenoid (10) from Cyclocarya paliurus leaves. Norqingqianliusus A and B (1 and 2) possess a unique 3,4-seco-dammarane-type C26 tetranortriterpenoid skeleton. The compounds were structurally characterized through modern spectroscopic techniques. Moreover, the potential mechanism of hypoglycemic activity was further explored by studying the effects on glucosamine-induced insulin resistant HepG2 cells. In vitro hypoglycemic effects of all of the isolates were investigated using insulin resistant HepG2 cells. The glucose consumption was significantly promoted by compound 10, in a dose-dependent manner, thus alleviating damage in IR-HepG2 cells. Besides, it reduced the PEPCK and GSK3β gene expression, involved in glucose metabolism. The anti-diabetic effects of the plant, utilized traditionally, can hence be attributed to the presence of nor-3,4-seco-dammarane triterpenoids in the leaves.