Echinatin Alleviates Experimental Pulmonary Hypertension by PPARγ Pathway Activation

The peroxisome proliferator-activated receptor gamma (PPARγ) signaling pathway plays a pivotal role in regulating the proliferation, apoptosis, inflammation, and metabolism of pulmonary arterial smooth muscle cells (PASMCs), suggesting its central involvement in the pathogenesis of pulmonary hypertension (PH). Although PPARγ agonists have shown promising therapeutic effects in preclinical models, their clinical translation remains challenging. Echinatin (Ecn), a natural flavonoid compound, has been reported to exhibit anti-inflammatory, antioxidant, and anti-proliferative properties by modulating multiple signaling pathways in various disease models. However, its therapeutic potential and mechanisms of action in PH remain unclear. This study systematically investigated the therapeutic effects and underlying mechanisms of Ecn in two established PH rat models: SuHx-PH and MCT-PH. The results demonstrated that Ecn significantly improved hemodynamic parameters, reduced right ventricular systolic pressure, alleviated right ventricular hypertrophy, and mitigated pulmonary vascular remodeling in both models. Transcriptomic analysis further revealed that Ecn activated the PPARγ signaling pathway and reduced oxidative stress in lung tissue. In vitro experiments showed that Ecn inhibited abnormal PASMC proliferation and migration while promoting apoptosis. Molecular docking and surface plasmon resonance experiments confirmed that Ecn specifically binds to the PPARγ ligand-binding domain and enhances its nuclear transcriptional activity. In conclusion, this study demonstrates that Ecn acts as a partial agonist of PPARγ, exhibiting strong binding affinity for the receptor and ameliorating hemodynamic abnormalities and pulmonary vascular remodeling in experimental PH models. These findings provide a robust experimental foundation for considering Ecn as a potential therapeutic agent for PH and offer valuable insights for the development of PPARγ-targeted therapies.