Beta-Sitosterol Facilitates GLUT4 Vesicle Fusion on the Plasma Membrane via the Activation of Rab/IRAP/Munc 18 Signaling Pathways in Diabetic Gastrocnemius Muscle of Adult Male Rats

Uncovering the mechanism of Naoxintong capsule against hypertension based on network analysis and in vitro experiments

Naoxintong capsule (NXT) is a clinical drug for the treatment of cardiovascular diseases, but its pharmacological mechanism against hypertension remains unclear. Data concerning the compounds and targets of NXT were obtained from the TCMSP and DrugBank, whereas data concerning hypertension-related genes were obtained from DisGeNET. The network was analyzed and established by STRING and Cytoscape, and function enrichment was analyzed by GO and KEGG analysis. Molecular docking was performed to analyze the interaction between ingredients and targets, cellular activity was evaluated by MTT assay, and RT-qPCR and western blot were used to evaluate the expressions of related genes. The results showed that 146 active therapeutic components can target hypertension-related genes, and we found that core genes were mainly involved in the metabolism of lipids, lipopolysaccharides, the inflammatory signaling pathway, and the oxidative stress pathway. In addition, there was high affinity between the components of NXT and targets of hypertension, where the former can increase cell viability and reduce the expressions of NOX4, MCP-1, BAX, TNF-α and IL-1β. Moreover, NXT inhibited the expressions of IL-6 and Fis1, as well as increased the expression of MCL-1. These results revealed the active compounds, hypertension targets, signaling pathways, and molecular mechanisms of NXT for treating hypertension, offering references for the clinical application of NXT and the treatment of hypertension.

Retracted: Beta-Sitosterol Facilitates GLUT4 Vesicle Fusion on the Plasma Membrane via the Activation of Rab/IRAP/Munc 18 Signaling Pathways in Diabetic Gastrocnemius Muscle of Adult Male Rats

[This retracts the article DOI: 10.1155/2022/7772305.].

β-Sitosterol mitigates hepatocyte apoptosis by inhibiting endoplasmic reticulum stress in thioacetamide-induced hepatic injury in γ-irradiated rats

The endoplasmic reticulum (ER) controls many biological functions besides maintaining the function of liver cells. Various studies reported the role of the ER stress and UPR signaling pathway in various liver diseases via triggering hepatocytes apoptosis. This study aims to investigate the suppressive effect of β-sitosterol (βS) on apoptosis associated with liver injury and ER stress.

METHODS

Liver damage in rats was induced by TAA (150 mg/kg I.P twice a week/3 weeks) and γ-irradiation (single dose 3.5 Gy) and treated with βS (20 mg/kg daily for 30 days). Serum aminotransferase activity, lipid profile and lipid metabolic factors were measured beside liver oxidative stress and inflammatory markers. Moreover, the hepatic expression of ER stress markers (inositol-requiring enzyme 1 alpha (IRE1α), X-box-binding protein 1 (XBP1) and CCAAT/enhancer binding protein homologous protein (CHOP) and apoptotic markers were detected together with histopathological examination.

RESULTS

βS diminished the aminotransferase activity, the oxidative stress markers as well as the inflammatory mediators. Furthermore, βS lowered the circulating TG and TC and the hepatic lipotoxicity via the suppression of lipogenesis (Srebp-1c) and improved the β-oxidation (Pparα and Cpt1a) together with the mitochondrial biogenesis (Pgc-1 α). Moreover, the upregulated levels of ER stress markers were reduced upon treatment with βS, which consequently attenuated hepatic apoptosis.

CONCLUSION

βS relieves hepatic injury, ameliorates mitochondrial biogenesis, and reduces lipotoxicity and apoptosis via inhibition of CHOP and ER stress response.

Glucose Uptake Is Increased by Estradiol Dipropionate in L6 Skeletal Muscle Cells

GLUT4 is an important glucose transporter, which is closely related to insulin resistance and type 2 diabetes. In this study, we investigated the mechanism of Estradiol Dipropionate (EDP) on uptake of glucose in L6 skeletal muscle cells. In our study, we confirmed that EDP promoted uptake of glucose in L6 skeletal muscle cells in both normal and insulin resistant models. Western blot indicated that EDP accelerated GLUT4 expression and significantly activated AMPK and PKC phosphorylation; the expression of GLUT4 was significantly inhibited by AMPK inhibitor compound C and PKC inhibitor Gö6983, but not by Wortmannin (Akt inhibitor). Meanwhile, EDP boosted GLUT4 expression, and also increased intracellular Ca²⁺ levels. In the presence of 2 mM, 0 mM extracellular Ca²⁺ and 0 mM extracellular Ca²⁺ + BAPTA-AM, the involvement of intracellular Ca²⁺ levels contribute to EDP-induced GLUT4 expression and fusion with plasma membrane. Therefore, this study investigated whether EDP promoted GLUT4 expression through AMPK and PKC signaling pathways, thereby enhancing GLUT4 uptake of glucose and fusion into plasma membrane in L6 skeletal muscle cells. In addition, both EDP induced GLUT4 translocation and uptake of glucose were Ca²⁺ dependent. These findings suggested that EDP may be potential drug for the treatment of type 2 diabetes.

Bioactive Components in Whole Grains for the Regulation of Skeletal Muscle Function

Skeletal muscle plays a primary role in metabolic health and physical performance. Conversely, skeletal muscle dysfunctions such as muscular dystrophy, atrophy and aging-related sarcopenia could lead to frailty, decreased independence and increased risk of hospitalization. Dietary intervention has become an effective approach to improving muscle health and function. Evidence shows that whole grains possess multiple health benefits compared with refined grains. Importantly, there is growing evidence demonstrating that bioactive substances derived from whole grains such as polyphenols, γ-oryzanol, β-sitosterol, betaine, octacosanol, alkylresorcinols and β-glucan could contribute to enhancing myogenesis, muscle mass and metabolic function. In this review, we discuss the potential role of whole-grain-derived bioactive components in the regulation of muscle function, emphasizing the underlying mechanisms by which these compounds regulate muscle biology. This work will contribute toward increasing awareness of nutraceutical supplementation of whole grain functional ingredients for the prevention and treatment of muscle dysfunctions.