Ligustilide targets SMAD3, obstructing vascular fibrosis process in preventing atherosclerosis

Atherosclerosis is a persistent inflammatory state accompanied by lipid overload. Vascular fibrosis is one of the primary causes of atherosclerosis development. Although ligustilide (Lig) was shown to exert obvious antiatherogenic effects in previous studies, its precise mechanism has not been comprehensively discussed. In this paper, pharmacologic studies were performed to explore the pharmacodynamic effects of Lig on protecting aorta vascular wall structures and modulating serum inflammatory factors in ApoE-/- mice. Chemical proteomics based on a Lig-derived photoaffinity labelling (Lig-PAL) probe were applied to identify potential therapeutic targets. Mothers against decapentaplegic homologue 3 (SMAD3), which is closely related to the development of vascular fibrosis and atherosclerosis, was identified as a potential target of Lig. Lig suppressed the phosphorylation and nuclear translocation of SMAD3 by blocking the interaction between SMAD3 and transforming growth factor-β (TGF-β) receptor 1, thereby inhibiting the collagen synthesis process, preventing vascular fibrosis and improving atherosclerosis. The quantitative proteomics results from Lig-treated atherosclerotic ApoE-/- mice also indicated that Lig inhibits the expression of collagens I and III, interferes with collagen fibril organization processes and protects the aorta from vascular fibrosis. Hence, developing a novel SMAD3 inhibitor may present another therapeutic option for preventing atherosclerosis.