Network pharmacology, molecular docking, and experimental verification to reveal the mechanism of colquhounia root tablet in the treatment of diabetic nephropathy

Diabetic nephropathy (DN) is one of the most common microvascular complications of diabetes mellitus. Colquhounia Root Tablet (CRT), one of the Tripterygium wilfordii Hook F. (TwHF)-based therapeutics, has exhibited various functions in DN. However, the pharmacological mechanisms underlying its effects are still unclear. The bioactive compounds and targets of CRT were obtained from the TCMSP database, HERB-National Genomics Data Center, and SwissTargetPrediction database. The targets of DN were obtained from the DisGeNET database, Genecards database, and OMIM database. Potential therapeutic targets for CRT against DN were identified by intersecting the above targets. Protein-protein interaction (PPI), Gene ontology (GO) functional annotation, and Kyoto Encyclopedia of Genes Genomes (KEGG) enrichment analysis were performed to explore the underlying mechanism. Molecular docking assessed the binding ability between bioactive compounds and targets. Network pharmacology analysis predicted that the overlap between CRT and DN targets yielded 163 therapeutic targets. STAT3, IL1B, JUN, IL6, TNF, HIF1A, CASP3, PPARG, and BCL2 were identified as the core targets through PPI. KEGG enrichment analysis revealed that the AGEs/RAGE signaling was the prominent pathway for CRT against DN. Molecular docking indicated hypodiolide A had the lowest binding energy and the most stable binding affinity towards HIF1A. Furthermore, AGEs-induced human podocytes were treated with different concentrations of CRT to validate the predicted signaling pathway. Results showed that CRT exerted protective effects against podocyte injury, angiogenesis, and epithelial-mesenchymal transition (EMT) by regulating the AGEs/RAGE/RhoA/RCOK signaling pathway. However, in vivo studies are needed to reveal the safety and efficacy of CRT in DN.