Asiaticoside reduces autophagy and improves memory in a rat model of dementia through mTOR signaling pathway regulation

Background: Type 2 Diabetes Mellitus (T2DM) is a world-wide metabolic disease with no cure from drugs and treatment. In China, The Traditional Chinese Medicine (TCM) herbal formulations have been used to treat T2DM for centuries. Methods: In this study, we proposed a formula called ShenQi Compound (SQC), which has been used in clinical therapeutics in China for several years. We evaluated the effect of SQC in a spontaneous diabetic rat model (GK rats) by detecting a series of blood indicators and performing histological observations. Meanwhile, the gene microarray and RT-qPCR experiments were used to explore the molecular mechanism of SQC treatment. In addition, western medicine, sitagliptin was employed as a comparison. Results: The results indicated that SQC and sitagliptin could effectively improve the serum lipid (blood Total Cholesterol (TC) and blood Triglycerides (TG)), hormone levels (serum insulin (INS), Glucagon (GC) and Glucagon-Like Peptide-1 (GLP-1)), alleviated the inflammatory response (hypersensitive C-Reactive Protein (hsCRP)), blood glucose fluctuation (Mean Blood Glucose (MBG), standard deviation of blood glucose (SDBG) and Largest Amplitude of plasma Glucose Excursions (LAGE)), pancreatic tissue damage and vascular injury for T2DM. Compared with sitagliptin, SQC achieved a better effect on blood glucose fluctuation (p<0.01). Meanwhile, the gene microarray and RT-qPCR experiments indicated that SQC and sitagliptin may improve the T2DM through affecting the biological functions related to apoptosis and circadian rhythm. Moreover, SQC might be able to influence the mTOR signaling pathway by regulating Pik3r1, Ddit4 expression. Conclusion: All these results indicate that SQC is an effective therapeutic drug on T2DM. Notably, SQC presents an obvious blood glucose fluctuation-preventing ability, which might be derived from the regulation of the mTOR signaling pathway.

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Dihydromyricetin promotes autophagy and attenuates renal interstitial fibrosis by regulating miR-155-5p/PTEN signaling in diabetic nephropathy

Bosnian Journal of Basic Medical Sciences ◽

10.17305/bjbms.2019.4410 ◽

2019 ◽

Author(s):

Liming Guo ◽

Kuibi Tan ◽

Qun Luo ◽

Xu Bai

Keyword(s):

Diabetic Nephropathy ◽

Signaling Pathway ◽

Rat Model ◽

Interstitial Fibrosis ◽

Mtor Signaling ◽

Luciferase Assay ◽

Luciferase Reporter ◽

Mtor Signaling Pathway ◽

Renal Interstitial Fibrosis ◽

Gene Assay

Diabetic nephropathy (DN) is the most common complication of diabetes and is prone to kidney failure. Dihydromyricetin (DHM) has been reported to have a variety of pharmacological activities. This study aims to explore the effect of DHM on DN and the underlying molecular mechanism. An in vivo DN rat model was established. The degree of renal interstitial fibrosis (RIF) was detected by hematoxylin-eosin (HE) staining, Masson's trichrome staining, and immunohistochemistry (IHC). In vitro, NRK-52E cells were divided into four groups: normal glucose (NG), high glucose (HG), HG+DHM, and HG+rapamycin (autophagy inhibitor). The levels of autophagy- and fibrosis-related proteins were analyzed by western blotting. The expression of miR-155-5p and phosphatase and tensin homolog deleted on chromosome ten (PTEN) and their relationship were assessed by quantitative reverse transcription (qRT)-PCR and dual luciferase reporter gene assay. Our results showed that RIF was increased in DN rat model and in HG-induced NRK-52E cells. DHM treatment attenuated the increased RIF and also increased autophagy. MiR-155-5p expression was increased, while PTEN expression was decreased in DN rat and cell model, and DHM reversed both effects. Dual luciferase assay showed that PTEN was the target gene of miR-155-5p. DHM inhibited HG-induced fibrosis and promoted autophagy by inhibiting miR-155-5p expression in NRK-52E cells. In addition, DHM promoted autophagy by inhibiting the PI3K/AKT/mTOR signaling pathway. In conclusion, DHM promotes autophagy and attenuates RIF by regulating the miR-155-5p/PTEN signaling and PI3K/AKT/mTOR signaling pathway in DN.

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