Identification of the active compounds and drug targets of Chinese medicine in heart failure based on the PPARs-RXRα pathway

Ethnopharmacological relevance: Danqi Pill (DQP), commonly known as a routinely prescribed traditional Chinese medicine (TCM), is composed of Salviae Miltiorrhizae Radix et Rhizoma and Notoginseng Radix et Rhizoma and effective in treating heart failure (HF) clinically due to their multicompound and multitarget properties. However, the exact active compounds and corresponding targets of DQP are still unknown.

Aim of the study: This study aimed to investigate active compounds and drug targets of DQP in heart failure based on the PPARs-RXRα pathway.

Materials and methods: Network pharmacology was used to predict the compound-target interactions of DQP. Left anterior descending (LAD)-induced HF mouse model and oxygen-glucose deprivation/recovery (OGD/R)-induced H9C2 model were constructed to screen the active compounds of DQP.

Results: According to BATMAN-TCM (a bioinformatics analysis tool for molecular mechanism of traditional Chinese medicine we previously developed), 24 compounds in DQP were significantly enriched in the peroxisome proliferator activated receptors-retinoid X receptor α (PPARs-RXRα) pathway. Among them, Ginsenoside Rb3 (G-Rb3) had the best pharmacodynamics against OGD/R-induced loss of cell viability, and it was selected to verify the compound-target interaction. In HF mice, G-Rb3 protected cardiac functions and activated the PPARs-RXRα pathway. In vitro, G-Rb3 protected against OGD/R-induced reactive oxygen species (ROS) production, promoted the expressions of RXRα and sirtuin 3 (SIRT3), thereafter improved the intracellular adenosine triphosphate (ATP) level. Immunofluorescent staining demonstrated that G-Rb3 could activate RXRα, and facilitate RXRα shifting to the nucleus. HX531, the specific inhibitor of RXRα, could abolish the protective effects of G-Rb3 on RXRα translocation. Consistently, the effect was also confirmed on RXRα siRNA cardiomyocytes model. Moreover, surface plasmon resonance (SPR) assays identified that G-Rb3 bound directly to RXRα with the affinity of KD = 10 × 10^-5 M.

Conclusion: By integrating network pharmacology and experimental validation, we identified that as the major active compound of DQP, G-Rb3 could ameliorate ROS-induced energetic metabolism dysfunction, maintain mitochondrial function and facilitate energy metabolism via directly targeting on RXRα. This study provides a promising strategy to dissect the effective patterns for TCM and finally promote the modernization of TCM.