Kun-Dan Decoction Ameliorates Insulin Resistance by Activating AMPK/mTOR-Mediated Autophagy in High-Fat Diet-Fed Rats

Hotspots and future trends of autophagy in Traditional Chinese Medicine: A Bibliometric analysis

Objective

To discuss the hotspots and future trends of autophagy in traditional Chinese medicine (TCM) and provide a reference for researchers in this field.

Method

Using visual analysis tools, metrological statistics and visual research on the pertinent literature in the area of autophagy use in TCM were undertaken in the core collection database of the Web of Science. By examining the authors, keywords, research circumstances, research hotspots, and trends of linked research, the use of autophagy in TCM was investigated.

Results and Conclusions

A total of 916 studies were included, among which Beijing University Chinese Medicine was the largest number of advantageous research institutions, followed by Shanghai University Traditional Chinese Medicine and Guangzhou University Chinese Medicine.The keywords of literature research primarily comprise apoptosis, activation, inhibition, pathway, mechanism, oxidative stress, proliferation, NF-κB, cancer, mtor, etc. At present, the research on autophagy in the field of TCM is increasing on a year-to-year basis. The research has focused on the role played by TCM in malignant tumors, atherosclerosis, Alzheimer's disease through autophagy, and the regulation of autophagy signaling pathways (e.g., PI3K/AKT/mTOR signaling pathway, TLR4 signaling pathway,nrf2 signaling pathway and NF-κB signaling pathway). In the future, the therapeutic effect of TCM on chemotherapy-resistant tumor cells through autophagy pathway, the role of TCM mediating mitophagy and activating autophagy function, and the therapeutic effect of TCM components represented by luteolin on tumors, asthma, myocardial injury and other diseases through autophagy mechanism will be the research hotspots in the future.

The 15-hydroxyprostaglandin dehydrogenase inhibitor SW033291 ameliorates abnormal hepatic glucose metabolism through PGE2-EP4 receptor-AKT signaling in a type 2 diabetes mellitus mouse model

Type 2 diabetes mellitus (T2DM) is associated with high rates of morbidity and mortality worldwide. Prostaglandin E₂ (PGE₂) is a lipid signaling molecule that can ameliorate the symptoms of some metabolic diseases, including T2DM, and improve tissue repair and regeneration. Although SW033291 can increase PGE₂ levels through its action as a small molecule inhibitor of the PGE₂-degrading enzyme 15-hydroxyprostaglandin dehydrogenase, its effects on T2DM remain unclear. In the present study, we evaluated whether SW033291 treatment exerts a protective effect against T2DM and explored the underlying mechanisms. A T2DM mouse model was established using a high-fat diet combined with streptozotocin treatment. Palmitic acid-treated LO2 cells were used as an insulin-resistant cell model. SW033291 treatment reduced body weight and fasting blood glucose levels as well as serum triglyceride, total cholesterol, and low-density lipoprotein cholesterol levels in vivo. In addition to ameliorating glucose and insulin tolerance, SW033291 treatment reversed the T2DM-induced decrease in glycogen synthesis and increase in gluconeogenesis in the liver. Furthermore, SW033291 administration increased hepatic glycogen synthase kinase 3 beta (GSK3β) phosphorylation levels to promote glycogen synthesis. SW033291 treatment also inhibited gluconeogenesis by upregulating AKT serine/threonine kinase (AKT) and forkhead box O1 (FOXO1) phosphorylation and reducing glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 expression in the livers of T2DM model mice. Additionally, SW033291 treatment improved abnormal hepatic glucose metabolism through the PGE₂-EP4 receptor-AKT-GSK3β/FOXO1 signaling pathway in vitro. These results suggest a novel role of SW033291 in improving T2DM and support its potential as a novel therapeutic agent.

Effects of high-fat diet-induced diabetes on autophagy in the murine liver: A systematic review and meta-analysis

AIMS

We conducted a meta-analysis to investigate whether diabetes induced by a high-fat diet (HFD) has the potential to alter the process of autophagy in the murine liver.

METHODS

A systematic literature search was performed with electronic databases (PubMed, EMBASE, Web of Science). Study design, population, intervention, outcome, and risk of bias were analyzed. Given the availability of studies, a quantitative meta-analysis including 23 studies was performed.

KEY FINDINGS

The search found 5754 articles, with 48 matching the eligibility criteria, comprising of 1033 animals. The meta-analysis showed that diabetic murines fed with HFD presented an absence of p62 degradation (SMD 4.63, 95 % CI 2.02 to 7.24, p = 0.0005; I² = 77 %), higher expression of p-mTOR/mTOR (SMD 5.20, 95 % CI 1.00 to 9.39, p = 0.01; I² = 78 %), and a decreased p-AMPK/AMPK ratio (SMD -2.02, 95 % CI -3.96 to -0.09, p = 0.04; I² = 85 %) when compared to nondiabetic murines. When associated with streptozotocin, the animals presented decreased ATG-7 and LC3-II. The meta-regression results showed a decrease in autophagy responses due to increased glycemic levels, fat content, and long-term exposure to HFD, and advanced animal age. The common and species-specific protein responses were also consistent with the inhibition of autophagy.

SIGNIFICANCE

The normal process of autophagy mechanisms in the liver is less competent after HFD consumption. The destabilization of (auto)phagolysosomes contributes to the perpetuation of diabetes, metabolic dysfunction-associated fatty liver disease, and cell death.

Mitophagy: A potential therapeutic target for insulin resistance

Glucose and lipid metabolism disorders caused by insulin resistance (IR) can lead to metabolic disorders such as diabetes, obesity, and the metabolic syndrome. Early and targeted intervention of IR is beneficial for the treatment of various metabolic disorders. Although significant progress has been made in the development of IR drug therapies, the state of the condition has not improved significantly. There is a critical need to identify novel therapeutic targets. Mitophagy is a type of selective autophagy quality control system that is activated to clear damaged and dysfunctional mitochondria. Mitophagy is highly regulated by various signaling pathways, such as the AMPK/mTOR pathway which is involved in the initiation of mitophagy, and the PINK1/Parkin, BNIP3/Nix, and FUNDC1 pathways, which are involved in mitophagosome formation. Mitophagy is involved in numerous human diseases such as neurological disorders, cardiovascular diseases, cancer, and aging. However, recently, there has been an increasing interest in the role of mitophagy in metabolic disorders. There is emerging evidence that normal mitophagy can improve IR. Unfortunately, few studies have investigated the relationship between mitophagy and IR. Therefore, we set out to review the role of mitophagy in IR and explore whether mitophagy may be a potential new target for IR therapy. We hope that this effort serves to stimulate further research in this area.

Isosteviol sodium attenuates high fat/high cholesterol-induced myocardial dysfunction by regulating the Sirt1/AMPK pathway

A fat-rich diet triggers obesity, and promotes cardiomyocyte injury. Till now, no prior investigations suggested a beneficial role of Isosteviol Sodium (STVNa) in cardiac activity in high fat diet (HFD)-exposed obese rats. However, there is evidence that STVNa accelerates healing of multiple tissue injuries. Herein, we explored the underlying mechanism behind the STVNa-based protection against HFD-induced myocardial dysfunction (MCD) in a rat model of myocardial injury. We employed dosages of 1, 10, and 20 mg/kg STVNa to treat MCD in rats fed with a HFD. Based on our results, STVNa repressed MCD (as indicated by ecocardiographic analysis), myocardium function, pathological structure, and myocardial enzymes. Mechanistically, the STVNa-mediated protection against HFD-induced MCD involved inhibition of inflammation and oxidative stress. Furthermore, using Western blot analysis, we revealed that the critical members of the Sirt1/AMPK network were markedly activated in the STVNa-treated group, relative to HFD-fed controls. Collectively, these evidences suggested that the STVNa offered strong protection against HFD-induced MCD. Moreover, this effect was mediated by the activation of the Sirt1/AMPK network, which, in turn, promoted lipid metabolism.

Network Pharmacology and Experimental Verification Strategies to Illustrate the Mechanism of Jian-Pi-Yi-Shen Formula in Suppressing Epithelial-Mesenchymal Transition

Jian-Pi-Yi-Shen formula (JPYSF), a traditional Chinese medicine, has been recommended to treat renal fibrosis for decades. Previous studies had shown that JPYSF could inhibit epithelial–mesenchymal transition (EMT), an important regulatory role in renal fibrosis. However, the mechanism of JPYSF action is largely unknown. In this study, network pharmacology and experimental verification were combined to elucidate and identify the potential mechanism of JPYSF against renal fibrosis by suppressing EMT at molecular and pathway levels. Network pharmacology was first performed to explore the mechanism of JPYSF against renal fibrosis targeting EMT, and then a 5/6 nephrectomy (5/6 Nx)-induced rat model of renal fibrosis was selected to verify the predictive results by Masson’s trichrome stains and western blot analysis. Two hundred and thirty-two compounds in JPYSF were selected for the network approach analysis, which identified 137 candidate targets of JPYSF and 4,796 known therapeutic targets of EMT. The results of the Gene Ontology (GO) function enrichment analysis included 2098, 88, and 133 GO terms for biological processes (BPs), molecular functions (MFs), and cell component entries, respectively. The top 10 enrichment items of BP annotations included a response to a steroid hormone, a metal ion, oxygen levels, and so on. Cellular composition (CC) is mainly enriched in membrane raft, membrane microdomain, membrane region, etc. The MF of JPYSF analysis on EMT was predominately involved in proximal promoter sequence-specific DNA binding, protein heterodimerization activity, RNA polymerase II proximal promoter sequence-specific DNA binding, and so on. The involvement signaling pathway of JPYSF in the treatment of renal fibrosis targeting EMT was associated with anti-fibrosis, anti-inflammation, podocyte protection, and metabolism regulation. Furthermore, the in vivo experiments confirmed that JPYSF effectively ameliorated interstitial fibrosis and inhibited the overexpression of α-SMA, Wnt3a, and β-catenin, and increased the expression of E-cadherin by wnt3a/β-catenin signaling pathway in 5/6 Nx-induced renal fibrosis rats. Using an integrative network pharmacology-based approach and experimental verification, the study showed that JPYSF had therapeutic effects on EMT by regulating multi-pathway, among which one proven pathway was the Wnt3a/β-catenin signaling pathway. These findings provide insights into the renoprotective effects of JPYSF against EMT, which could suggest directions for further research of JPYSF in attenuating renal fibrosis by suppressing EMT.

AMPK signaling in diabetes mellitus, insulin resistance and diabetic complications: A pre-clinical and clinical investigation

Diabetes mellitus (DM) is considered as a main challenge in both developing and developed countries, as lifestyle has changed and its management seems to be vital. Type I and type II diabetes are the main kinds and they result in hyperglycemia in patients and related complications. The gene expression alteration can lead to development of DM and related complications. The AMP-activated protein kinase (AMPK) is an energy sensor with aberrant expression in various diseases including cancer, cardiovascular diseases and DM. The present review focuses on understanding AMPK role in DM. Inducing AMPK signaling promotes glucose in DM that is of importance for ameliorating hyperglycemia. Further investigation reveals the role of AMPK signaling in enhancing insulin sensitivity for treatment of diabetic patients. Furthermore, AMPK upregulation inhibits stress and cell death in β cells that is of importance for preventing type I diabetes development. The clinical studies on diabetic patients have shown the role of AMPK signaling in improving diabetic complications such as brain disorders. Furthermore, AMPK can improve neuropathy, nephropathy, liver diseases and reproductive alterations occurring during DM. For exerting such protective impacts, AMPK signaling interacts with other molecular pathways such as PGC-1α, PI3K/Akt, NOX4 and NF-κB among others. Therefore, providing therapeutics based on AMPK targeting can be beneficial for amelioration of DM.