Iminostilbene, a Carbamazepine Intermediate, Alleviates Myocardial Fibrosis after Myocardial Infarction via Targeting Galectin3.

Myocardial infarction (MI) induces a strong injury response, resulting in a collagen-dominated scarring. A persistent myocardial fibrotic response induces heart failure. Myocardial fibroblasts are responsible for the deposition and remodeling of collagen and are important targets for limiting the fibrotic process after myocardial infarction. Iminostilbene (ISB), a small molecule and synthetic intermediate of carbamazepine, exhibits potent antiapoptotic, anti-inflammatory, and antioxidative effects. However, its role in cardiac fibrosis, target binding, and underlying mechanisms remains unclear. Objective: To evaluate the effect of iminostilbene on myocardial fibrosis after myocardial infarction (MI), we explored its target mechanism. Methods: The rat model of myocardial infarction was established by permanent ligation of the left anterior descending branch of coronary artery in vivo, and then iminostilbene or captopril was given for 2 weeks. Primary myocardial fibroblasts (CFs) were stimulated with 10 nM TGF-β1 in vitro to establish a myocardial fibrosis model. The PAL-CC-ABPP technique was used to fish for iminostilbene binding targets to further clarify its antifibrosis effect and mechanism. Results: Iminostilbene significantly improved cardiac function and inhibited pathological myocardial fibrosis in rats after myocardial infarction. Histological analysis, immunofluorescence, and Western blot results showed that iminostilbene treatment significantly decreased the expression of extracellular matrix (ECM)-associated proteins α-SMA and Collagen I in myocardial tissue. Further in vitro results confirmed that iminostilbene inhibited fibroblast activation. According to proteomic analysis, galectin-3 is a potential target of iminostilbene, and the specific binding was verified by competitive experiments and DARTS. In addition, in terms of the biological function of iminostilbene to galectin-3, iminostilbene decreased the expression of galectin-3 after myocardial infarction. Iminostilbene has an inhibitory effect on TGF-β1/smad3 downstream pathway of galectin-3, which can reduce the expression of TGF-β1 and inhibit the phosphorylation of Smad3 to alleviate myocardial fibrosis. Conclusion: Iminostilbene can be used to inhibit CFs activation through the Gal3/TGF-β1/Smad3 pathway, improve cardiac function, and alleviate cardiac fibrosis.