Betulinaldehyde inhibits vascular remodeling by regulating the microenvironment through the PLC1/Ca²⁺/MMP9 pathway

Background: Vascular remodeling plays a crucial role in the pathogenesis of several cardiovascular diseases (CVDs). Unfortunately, current drug therapies offer limited relief for vascular remodeling. Therefore, the development of innovative therapeutic strategies or drugs that target vascular remodeling is imperative. Betulinaldehyde (BA) is a triterpenoid with diverse biological activities, but its effects on vascular remodeling remain unclear. Objective: This study aimed to investigate the role of BA in vascular remodeling and its mechanism of action, providing valuable information for future applications of BA in the treatment of CVDs. Methods: Network pharmacology was used to predict the key targets of BA in vascular remodeling. The effect of BA on vascular remodeling was assessed in a rat model of balloon injury using hematoxylin and eosin staining, Masson staining, immunohistochemistry staining, and Western blotting. A phenotypic transformation model of vascular smooth muscle cells (VSMCs) was induced by platelet-derived growth factor-BB, and the functional impacts of BA on VSMCs were assessed via CCK-8, EdU, Wound healing, Transwell, and Western blotting. Finally, after manipulation of phospholipase C gamma1 (PLC gamma 1) expression, Western blotting and Ca2+ levels determination were performed to investigate the potential mechanism of action of BA. Results: The most key target of BA in vascular remodeling, matrix metalloproteinase 9 (MMP9), was identified through network pharmacology screening. Vascular remodeling was alleviated by BA in vivo and its effects were associated with decreased MMP9 expression. In vitro studies indicated that BA inhibited VSMC proliferation, migration, phenotypic transformation, and downregulated MMP9 expression. Additionally, BA decreased PLC gamma 1 expression and Ca2+ levels in VSMCs. However, after pretreatment with a phospholipase C agonist, BA's effects on down-regulating the expression of PLC gamma 1 and Ca2+ levels were inhibited, while the expression of MMP9 increased compared to that in the BA treatment group. Conclusion: This study demonstrated the critical role of BA in vascular remodeling. These findings revealed a novel mechanism whereby BA mediates its protective effects through MMP9 regulation by inhibiting the PLC gamma 1/ Ca2+/MMP9 signaling pathway. Overall, BA may potentially be developed into a novel medication for CVDs and may serve as a promising therapeutic strategy for improving recovery from CVDs by targeting MMP9.