Tangduqing Granules Attenuate Insulin Resistance and Abnormal Lipid Metabolism through the Coordinated Regulation of PPARγ and DGAT2 in Type 2 Diabetic Rats

Screening and identification of key biomarkers associated with endometriosis using bioinformatics and next-generation sequencing data analysis

Background

Endometriosis is a common cause of endometrial-type mucosa outside the uterine cavity with symptoms such as painful periods, chronic pelvic pain, pain with intercourse and infertility. However, the early diagnosis of endometriosis is still restricted. The purpose of this investigation is to identify and validate the key biomarkers of endometriosis.

Methods

Next-generation sequencing dataset GSE243039 was obtained from the Gene Expression Omnibus database, and differentially expressed genes (DEGs) between endometriosis and normal control samples were identified. After screening of DEGs, gene ontology (GO) and REACTOME pathway enrichment analyses were performed. Furthermore, a protein–protein interaction (PPI) network was constructed and modules were analyzed using the Human Integrated Protein–Protein Interaction rEference database and Cytoscape software, and hub genes were identified. Subsequently, a network between miRNAs and hub genes, and network between TFs and hub genes were constructed using the miRNet and NetworkAnalyst tool, and possible key miRNAs and TFs were predicted. Finally, receiver operating characteristic curve analysis was used to validate the hub genes.

Results

A total of 958 DEGs, including 479 upregulated genes and 479 downregulated genes, were screened between endometriosis and normal control samples. GO and REACTOME pathway enrichment analyses of the 958 DEGs showed that they were mainly involved in multicellular organismal process, developmental process, signaling by GPCR and muscle contraction. Further analysis of the PPI network and modules identified 10 hub genes, including vcam1, snca, prkcb, adrb2, foxq1, mdfi, actbl2, prkd1, dapk1 and actc1. Possible target miRNAs, including hsa-mir-3143 and hsa-mir-2110, and target TFs, including tcf3 (transcription factor 3) and clock (clock circadian regulator), were predicted by constructing a miRNA-hub gene regulatory network and TF-hub gene regulatory network.

Conclusions

This investigation used bioinformatics techniques to explore the potential and novel biomarkers. These biomarkers might provide new ideas and methods for the early diagnosis, treatment and monitoring of endometriosis.

Impact of Lipids on Insulin Resistance: Insights from Human and Animal Studies

Insulin resistance (IR) is a complex pathological condition central to metabolic diseases such as type 2 diabetes mellitus (T2DM), cardiovascular disease, non-alcoholic fatty liver disease, and polycystic ovary syndrome (PCOS). This review evaluates the impact of lipids on insulin resistance (IR) by analyzing findings from human and animal studies. The articles were searched on the PubMed database using two keywords: (1) "Role of Lipids AND Insulin Resistance AND Humans" and (2) "Role of Lipids AND Insulin Resistance AND Animal Models". Studies in humans revealed that elevated levels of free fatty acids (FFAs) and triglycerides (TGs) are closely associated with reduced insulin sensitivity, and interventions like metformin and omega-3 fatty acids show potential benefits. In animal models, high-fat diets disrupt insulin signaling and increase inflammation, with lipid mediators such as diacylglycerol (DAG) and ceramides playing significant roles. DAG activates protein kinase C, which eventually impairs insulin signaling, while ceramides inhibit Akt/PKB, further contributing to IR. Understanding these mechanisms is crucial for developing effective prevention and treatment strategies for IR-related diseases.

Total Astragalus saponins can reverse type 2 diabetes mellitus-related intestinal dysbiosis and hepatic insulin resistance in vivo

Objective

Intestinal flora homeostasis in rats with type 2 diabetes mellitus (T2DM) was evaluated to explore the effects of total Astragalus saponins (TAS) on hepatic insulin resistance (IR).

Methods

Six-week-old male Sprague-Dawley rats were fed high-fat and high-sugar diet for 4 weeks and intraperitoneally injected with streptozotocin to induce T2DM, and they were then randomly divided into control, model, metformin, and TAS groups. Stool, serum, colon, and liver samples were collected after 8 weeks of drug administration for relevant analyses.

Results

TAS reduced fasting blood glucose, 2-hour postprandial blood glucose, area under the curve of oral glucose tolerance test, glycated serum protein, homeostasis model assessment of insulin resistance, total cholesterol, triglyceride, and low-density lipoprotein cholesterol levels in T2DM rats but increased insulin, C-peptide, and high-density lipoprotein cholesterol levels. Moreover, TAS improved the morphology and structure of liver and colon tissues and improved the composition of the intestinal microbiome and bacterial community structure at different taxonomic levels. In addition, TAS increased the protein expression of hepatic IRS-1, PI3K, PDK1, and p-AKT and decreased the protein expression of p-GSK-3β. Meanwhile, TAS increased the mRNA expression of liver PDK1, PI3K, and GS and decreased the mRNA expression of GSK-3β.

Conclusion

TAS can ameliorate T2DM-related abnormal glucose and blood lipid metabolism, intestinal dysbiosis, and IR.

Natural products as novel anti-obesity agents: insights into mechanisms of action and potential for therapeutic management

Obesity affects more than 10% of the adult population globally. Despite the introduction of diverse medications aimed at combating fat accumulation and obesity, a significant number of these pharmaceutical interventions are linked to substantial occurrences of severe adverse events, occasionally leading to their withdrawal from the market. Natural products serve as attractive sources for anti-obesity agents as many of them can alter the host metabolic processes and maintain glucose homeostasis via metabolic and thermogenic stimulation, appetite regulation, pancreatic lipase and amylase inhibition, insulin sensitivity enhancing, adipogenesis inhibition and adipocyte apoptosis induction. In this review, we shed light on the biological processes that control energy balance and thermogenesis as well as metabolic pathways in white adipose tissue browning, we also highlight the anti-obesity potential of natural products with their mechanism of action. Based on previous findings, the crucial proteins and molecular pathways involved in adipose tissue browning and lipolysis induction are uncoupling protein-1, PR domain containing 16, and peroxisome proliferator-activated receptor-γ in addition to Sirtuin-1 and AMP-activated protein kinase pathway. Given that some phytochemicals can also lower proinflammatory substances like TNF-α, IL-6, and IL-1 secreted from adipose tissue and change the production of adipokines like leptin and adiponectin, which are important regulators of body weight, natural products represent a treasure trove for anti-obesity agents. In conclusion, conducting comprehensive research on natural products holds the potential to accelerate the development of an improved obesity management strategy characterized by heightened efficacy and reduced incidence of side effects.

X-box binding protein 1: A new metabolic mediator and drug target of metformin?

Accumulating evidence has demonstrated that metformin improved hypertriglyceridemia. The present study aim to investigate the molecular mechanism by which metformin improves hypertriglyceridemia via regulation of diacylglycerol O-acyltransferase 2 (DGAT2) and X-box binding protein 1 (XBP1) in the liver and whether AMP-activated protein kinase (AMPK) is involved. Mice were fed a high-fat diet (HFD) or high-fat diet with metformin for 5 weeks to evaluate the effect of metformin on triglyceride (TG) levels and expression of DGAT2 and XBP1 in the liver. In vitro HepG2 cells or XBP1 knockout AML12 hepatocytes were stimulated with metformin, palmitic acid or small interfering RNA inducing XBP1 knockdown, or dominant-negative mutant AMPK plasmid. Metformin treatment reduced hepatic TG levels in the liver of HFD-fed mice. Expression of nuclear and cytoplasmic XBP1 protein and its downstream target gene DGAT2 decreased in the liver of HFD-fed mice and HepG2 cells after metformin treatment. AMPK inactivation or overexpression of XBP1 attenuates this effect. Our preliminary results demonstrate that metformin activates AMPK to reduce TG synthesis by inhibiting the XBP1-mediated DGAT2 pathway, at least in part, suggesting that XBP1 is a new metabolic mediator for metformin treatment of hypertriglyceridemia and associated metabolic disease.

Development of an in vitro insulin resistance dissociated model of hepatic steatosis by co-culture system

The evidence shows that there is an associated relationship between hepatosteatosis and insulin resistance. While some existing genetic induction animal and patient models challenge this relationship, indicating that hepatosteatosis is dissociated from insulin resistance. However, the molecular mechanisms of this dissociation remain poorly understood due to a lack of available, reliable, and simplistic setup models. Currently, we used primary rat hepatocytes (rHPCs), co-cultured with rat hepatic stellate cells (HSC-T6) or human foreskin fibroblast cells (HFF-1) in stimulation with high insulin and glucose, to develop a model of steatosis charactered as dissociated lipid accumulation from insulin resistance. Oil-Red staining significantly showed intracellular lipid accumulated in the developed model. Gene expression of sterol regulatory element-binding protein 1c (SREBP1c) and elongase of very-long-chain fatty acids 6 (ELOVL6), key genes responsible for lipogenesis, were detected and obviously increased in this model. Inversely, the insulin resistance related genes expression included phosphoenolpyruvate carboxykinase 1 (PCK1), pyruvate dehydrogenase lipoamide kinase isozyme 4 (PDK4), and glucose-6-phosphatase (G6pase) were decreased, suggesting a dissociation relationship between steatosis and insulin resistance in the developed model. As well, the drug metabolism of this developed model was investigated and showed up-regulation of cytochrome P450 3A (CYP3A) and down-regulation of cytochrome P450 2E1 (CYP2E1) and cytochrome P450 1A2 (CYP1A2). Taken together, those results demonstrate that the in vitro model of dissociated steatosis from insulin resistance was successfully created by our co-cultured cells in high insulin and glucose medium, which will be a potential model for investigating the mechanism of insulin resistance dissociated steatosis, and discovering a novel drug for its treatment.

Optimization of Porphyran Extraction from Pyropia yezoensis by Response Surface Methodology and Its Lipid-Lowering Effects

Macroalgae polysaccharides are phytochemicals that are beneficial to human health. In this study, response surface methodology was applied to optimize the extraction procedure of Pyropia yezoensis porphyran (PYP). The optimum extraction parameters were: 100 °C (temperature), 120 min (time), and 29.32 mL/g (liquid-solid ratio), and the maximum yield of PYP was 22.15 ± 0.55%. The physicochemical characteristics of PPYP, purified from PYP, were analyzed, along with its lipid-lowering effect, using HepG2 cells and Drosophila melanogaster larvae. PPYP was a β-type sulfated hetero-rhamno-galactan-pyranose with a molecular weight of 151.6 kDa and a rhamnose-to-galactose molar ratio of 1:5.3. The results demonstrated that PPYP significantly reduced the triglyceride content in palmitic acid (PA)-induced HepG2 cells and high-sucrose-fed D. melanogaster larvae by regulating the expression of lipid metabolism-related genes, reducing lipogenesis and increasing fatty acid β-oxidation. To summarize, PPYP can lower lipid levels in HepG2 cells and larval fat body (the functional homolog tissue of the human liver), suggesting that PPYP may be administered as a potential marine lipid-lowering drug.

Research progress of typical flavonoids in improving insulin resistance

Flavonoids are a large class of compounds that are widely found in many plants, including plants used in Chinese herbal medicines. Previous studies have revealed that flavonoids possess biomedical activities, including antioxidant, anti-cancer, anti-viral, and anti-inflammatory properties. They also have the functions of lowering lipids, lowering blood sugar, and improving insulin resistance. This article selects four typical compounds of flavonoids, namely baicalin, baicalein, quercetin, and rutin, and reviews their effects and mechanisms of action in improving insulin resistance. With a view for future clinical research on flavonoids as antidiabetic drugs, we therefore provide the theoretical basis for the development and application of flavonoids.