Modified weiling decoction inhibited excessive autophagy via AKT/mTOR/ULK1 pathway to alleviate T2DM: Integrating...

Weiling Decoction is a traditional Chinese herbal formula that has the function of removing dampness and transforming turbidity, and it is widely used in the treatment of metabolic diseases. The hypoglycemic and antihyperlipidemic effects of Modified Weiling Decoction (MWLD) have been clinically verified in patients with type 2 diabetes mellitus (T2DM), however, the molecular mechanism remains unclear.

To explore the hypoglycemic mechanism of MWLD based on integrative network pharmacology and experimental validation in vivo and in vitro.

The overlap between T2DM-related genes and target genes of MWLD were deemed to the potential targets of MWLD in alleviating T2DM. Protein-protein interaction analysis was performed to find the core targets from above-mentioned potential targets, and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and Gene Ontology (GO) analysis were carried out to gain the key pathways involved in the T2DM improvement by MWLD. T2DM mice and palmitic acid-induced HepG2 cells were employed to validate the mechanism of MWLD predicated by network pharmacology.

A total of 292 target genes from 113 bioactive compounds in MWLD were identified, among of which 42 genes were recognized as core genes of MWLD in ameliorating T2DM. KEGG analysis showed that the therapeutic effect of MWLD on T2DM may be associated with insulin resistance (IR), islet β cell dysfunction, AKT, and MAPK. We found that MWLD significantly reduced fasting blood glucose and improved oral glucose tolerance in T2DM mice. Meanwhile, MWLD activated the AKT/GSK3β pathway to increase liver glycogen production and improve glucose metabolism in T2DM mice. MWLD activated the AKT/mTOR/ULK1 signaling pathway and reversed the increase of autophagy associated proteins (LC3II, Beclin1, Cathepsin B, and LAMP2) in the liver of T2DM mice. Similar results were also confirmed palmitic acid-induced HepG2 cells, an in vitro model for IR. Conversely, AKT inhibitor MK2206 neutralized the effects of MWLD on autophagy and glucose uptake, which was consistent with these results that the main active components of MWLD show strong affinity with AKT1 analyzed by molecular docking.

Both in vivo and in vitro experiments showed that MWLD inhibited excessive autophagy through the AKT/mTOR/ULK1 pathway to improve hepatic IR, and stimulate liver glycogen production through AKT/GSK3β pathway.