Bellidifolin Improves Pulmonary Artery Smooth Muscle Cells Proliferation by Targeting the IGFBP5-Mediated...

Pulmonary hypertension (PH) is a progressive disease that severely compromises right ventricular function, characterized by two major pathological features: pulmonary arterial constriction and pulmonary arterial remodeling. Bellidifolin (BEL), a natural ketone compound, exhibits potent anti-inflammatory and antioxidant effects; however, its role in PH remains unexplored. This study evaluated the impact of BEL on the two pathological processes: pulmonary arterial constriction and pulmonary arterial remodeling. First, the effects of BEL on pulmonary arterial constriction were evaluated using wire myography. The study revealed that BEL (6-96 μmol/L) inhibited the contraction response of intact endothelial and denuded pulmonary arterial rings precontracted with norepinephrine (1 μmol/L) in a concentration-dependent manner. BEL (90 μmol/L) suppressed pulmonary constriction induced by intracellular calcium release and extracellular calcium influx. In cellular experiments, BEL inhibited the proliferation, migration, and phenotypic transformation of pulmonary arterial smooth muscle cells (PASMCs) induced by 10 μmol/L CoCl₂ (72 h), as evidenced by upregulation of the contractile phenotype markers α-SMA and SM22α and downregulation of the synthetic phenotype markers OPN, vimentin, and PCNA. Multi-omics analysis identified Aldh1A1, Mgp, Col4a6, and Igfbp5 as significantly enriched candidates. Among these candidates, Cellular Thermal Shift Assay demonstrated that BEL enhanced the thermal stability of Igfbp5 in PASMCs, suggesting that Igfbp5 may be a potential direct target of BEL. Moreover, KEGG pathway analysis revealed significant enrichment of the PI3K-AKT-mTOR pathway, which is known to be involved in cell proliferation and is regulated by Igfbp5. BEL may inhibit the PI3K-AKT-mTOR pathway by suppressing Igfbp5. The results indicate that BEL may regulate Igfbp5 to inhibit the PI3K-AKT-mTOR pathway, thereby exerting anti-proliferative and inhibitory effects on migration and phenotypic transformation.