Astragaloside IV Regulates Insulin Resistance and Inflammatory Response of Adipocytes via Modulating MIR-21/PTEN/PI3K/AKT Signaling.

BACKGROUND: The progression of Type 2 Diabetes Mellitus (T2DM) can lead to various complications. Compounds derived from natural products have been found to be effective in combatting T2DM. This study aimed to investigate the effects of Astragaloside IV (AS-IV) on insulin resistance and the inflammatory response of adipocytes. The study also aimed to determine the downstream signaling pathways involved. MATERIALS AND METHODS: The glucose consumption of adipocytes was assessed using a glucose assay kit. qRT-PCR, Western blot, and ELISA assays were used to measure mRNA and protein levels. The interaction between miR-21 and PTEN was assessed using a Dual-luciferase reporter assay. RESULTS: The results showed that AS-IV increased glucose consumption and the expression of GLUT-4 in adipocytes with insulin resistance in a concentration-dependent manner. However, ASIV decreased the protein levels of TNF-α and IL-6 in these cells. Additionally, AS-IV up-regulated miR-21 expression in adipocytes with insulin resistance in a concentration-dependent manner. Furthermore, miR-21 overexpression increased glucose consumption and GLUT-4 expression but decreased TNF-α and IL-6 protein levels in adipocytes. Conversely, miR-21 inhibition attenuated the AS-IV-induced increase in glucose consumption and GLUT-4 expression and the decrease in TNF- α and IL-6 protein levels in adipocytes. MiR-21 also inversely regulated PTEN in adipocytes, and PTEN overexpression had effects similar to miR-21 inhibition in AS-IV-treated adipocytes. Finally, AS-IV up-regulated p-PI3K and p-AKT protein expression in adipocytes, which was attenuated by miR-21 inhibition. CONCLUSION: The study concluded that AS-IV attenuated insulin resistance and the inflammatory response in adipocytes. The mechanistic studies indicated that AS-IV modulated the miR- 21/PTEN/PI3K/AKT signaling in adipocytes to exert these effects.

Astragaloside IV Regulates Insulin Resistance and Inflammatory Response of Adipocytes via Modulating CTRP3 and PI3K/AKT Signaling.

INTRODUCTION: Emerging evidence showed that adipocytes are important regulators in controlling insulin resistance in type 2 diabetes mellitus (T2DM). So far, compounds isolated from natural plants have been widely studied for their roles in alleviating T2DM-associated complications. This work evaluated the actions of astragaloside IV (AS-IV) on insulin resistance and inflammatory biomarker expression in adipocytes and explored the potential mechanisms. METHODS: Glucose consumption of the adipocytes was determined by a glucose assay kit; the mRNA expression levels of glucose transporter type 4 (GLUT-4), interleukin-6 (IL-6), TNF-α and C1q tumor necrosis factor-related protein 3 (CTRP3) were measured by quantitative real-time PCR (qRT-PCR); the protein levels were determined by western blot assay and enzyme-linked immunosorbent assay. RESULTS: AS-IV concentration-dependently increased glucose consumption in the insulin resistance adipocytes. Further qRT-PCR results showed that AS-IV concentration-dependently reduced adipocyte IL-6 and TNF-α expression. Moreover, GLUT-4 expression in adipocytes was also significantly upregulated by AS-IV. Furthermore, we found that AS-IV concentration-dependently increased CTRP3 expression in adipocytes. CTRP3 silence decreased glucose consumption, upregulated IL-6 and TNF-α expression and downregulated GLUT-4 mRNA expression in 200 µM AS-IV-treated adipocytes. Moreover, AS-IV treatment enhanced the activity of phosphoinositide 3-kinase (PI3K)/AKT signaling in adipocytes, which was markedly attenuated by CTRP3 silencing. Importantly, inhibition of PI3K/AKT signaling also attenuated AS-IV induced an increase in glucose consumption and GLUT-4 expression and a decrease in IL-6 and TNF-α expression of adipocytes. CONCLUSIONS: Collectively, our data indicated that AS-IV attenuated insulin resistance and inflammation in adipocytes via targeting CTRP3/PI3K/Akt signaling.

Protective effect of Jiaweibugan decoction against diabetic peripheral neuropathy.

Oxygen free radical damage is regarded as a direct or indirect common pathway associated with diabetic neuropathy and is the main cause of complications in peripheral neuropathies. We speculate that Jiaweibugan decoction has a significant effect in treating diabetic peripheral neuropathy through an anti-oxidative stress pathway. In this study, a diabetic rat model was established by intraperitoneal injection of streptozotocin. Rats were treated with Jiaweibugan decoction via intragastric administration. The levels of malondialdehyde and glutathione, which are indirect indexes of oxidative stress, in serum were determined using a colorimetric method. The expression levels of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase, which are oxidative stress associated factors, in the dorsal root ganglion of spinal S4-6 segments were evaluated by reverse-transcriptase polymerase chain reaction and immunohistochemistry. Results showed that, Jiaweibugan decoction significantly ameliorated motor nerve conduction velocity in diabetic rats, effectively decreased malondialdehyde levels in serum and the expression of nuclear factor kappa B p65 mRNA and p38 mitogen-activated protein kinase mRNA in the dorsal root ganglion, and increased glutathione levels in serum. Therefore, our experimental findings indicate that Jiaweibugan decoction plays an anti-oxidative stress role in the diabetic peripheral neuropathy process, which has a protective effect on peripheral nerve injury.