Acacetin Attenuates Lysophosphatidylcholine-Induced Vascular Smooth Muscle Cell Injury via Sirt1-Nrf2/p62 Signaling Axis

<b>Background:</b> Acacetin, a naturally occurring flavone present in various plants, is known as a promising drug candidate for cardiovascular disorders. Our previous study demonstrated that acacetin ameliorates atherosclerosis through endothelial cell protection; however, its pharmacological effects on vascular smooth muscle cells (VSMCs) remain unexplored. This study investigates the therapeutic potential of acacetin against lysophosphatidylcholine (LysoPC)-induced VSMC injury and elucidates the underlying molecular mechanisms. <b>Methods and Results:</b> Multiple biochemical techniques were employed in the present study. The results showed that acacetin significantly attenuated LysoPC-induced apoptosis and reactive oxygen species (ROS) generation in cultured VSMCs. Western blot analysis revealed that the cytoprotection of acacetin was associated with upregulated expression of antioxidant defense proteins, including nuclear factor erythroid 2-related factor 2 (Nrf2), catalase (CAT), NADPH quinone oxidoreductase 1 (NQO-1), and superoxide dismutase 1 (SOD1). Nrf2 silencing completely abolished these protective effects. Mechanistically, siRNA-silencing of Sirtuin 1 (Sirt1) abrogated acacetin-induced modulation of the Nrf2/Keap1/p62 signaling. In vivo validation using aortic tissues from high-fat-diet-fed ApoE^-/- mice confirmed that acacetin effectively suppressed VSMC apoptosis and ROS overproduction associated with restoring the downregulated Sirt1 expression levels. <b>Conclusions:</b> These findings establish a novel mechanistic paradigm wherein acacetin confers protection against LysoPC-induced VSMC apoptosis and oxidative stress through Sirt1-dependent activation of the Nrf2/p62 signaling pathway, suggesting that acacetin is a promising therapeutic drug candidate for atherosclerotic plaque stabilization.