Integrated Network Pharmacology and Targeted Metabolomics to Reveal the Mechanism of Nephrotoxicity of Triptolide

Triptolide (TP) is one of the important active components in Tripterygium Wilfordii Hook. f., which has strong anti-inflammatory and immunomodulatory effects. However, a large number of literatures have reported that TP is the main component of nephrotoxicity, and the mechanism of nephrotoxicity has not yet been revealed. Therefore, it is of great practical significance to clarify the toxicity mechanism of TP. This study integrated network pharmacology and targeted metabolomics to reveal the nephrotoxicity mechanism of TP. Firstly, network pharmacology screen 61 action targets that related to TP induced nephrotoxicity, which contain 39 direct targets and 22 indirect targets. Subsequently, based on a large-scale protein-protein interactions (PPI) and molecular docking validation, core targets were identified. Based on above targets and enrichment analysis, purine metabolism pathway, Toll-like receptor signaling pathway and NF-kappaB signaling pathway were found to play a pivotal role in triptolide-induced nephrotoxicity. After literature investigation, purine and pyrimidine metabolism pathway were closely related to kidney diseases. Therefore, by using the quantitative method of endogenous purine and pyrimidine previous established in the laboratory, a targeted metabolomic analysis of TP was carried out. Finally, six nephrotoxicity biomarkers, dihydroorotate, thymidine, 2-deoxyinosine, uric acid, adenosine and xanthine, were found. Combining the above results, the mechanisms underlying the nephrotoxicity of triptolide were speculated to be due to the over-consumption of xanthine and uric acid, which would result in a large amount of ROS being released in response to oxidative stress in the body. Furthermore, the activation of the Toll-like receptor signalling pathway promotes the phosphorylation of the downstream protein NF-κB and causes an inflammatory response that ultimately leads to nephrotoxicity.