Department of General Practice, The Fifth Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, PR China; Guangxi Key Laboratory of Diabetic Systems Medicine, Guilin Medical University, Guilin, Guangxi, PR China.
Department of General Practice, The Fifth Affiliated Hospital of Southern Medical University, Guangzhou, Guangdong, PR China.
Phytomedicine. 2024 Nov;134:155939. doi: 10.1016/j.phymed.2024.155939. Epub 2024 Aug 11.
Atherosclerosis (AS) is the most prevalent cardiovascular disease and remains the major contributor to death and mortality globally. Leonurine (LEO) is a unique alkaloid compound with protective effects on the cardiovascular system. However, the exact mechanisms underlying its cardiovascular-protecting action are still not fully elucidated. The methyltransferase 3 (METTL3), the catalytic core of the N6-methyladenosine modification (mA) methyltransferase complex, has been shown to inhibit autophagy and exacerbate the process of AS via regulation of mA modification of mRNA.
We aimed to determine whether the inhibited effect of LEO on AS is related to METTL3-mediated AKT1S1 stability.
The apolipoprotein E (ApoE) knockout mice was subjected to a high-fat diet (HFD), and THP-1 derived macrophages was exposed to oxidized low-density lipoprotein (ox-LDL), to establish the animal and cellular models of AS, respectively.
We found that LEO effectively improved AS and reduced the plaque area and inflammation via diminishing macrophage lipid accumulation and remodeling the lipid metabolism profile. LEO activated ox-LDL-induced macrophage autophagy, enhancing lipid metabolism decrease, according to the lipidomic and molecular biology analyses. Additionally, LEO caused a marked increase in autophagy marker levels in mouse models with advanced AS. Furthermore, we found that LEO reactivated autophagy and reversed lipid accumulation by suppressing METTL3 expression. The mA-seq from ox-LDL-induced macrophages showed that a total of five autophagy-related mRNA transcripts (AKT1S1, AKT1, RB1CC1, CFLAR, and MTMR4) were altered, and AKT1S1 was significantly upregulated by LEO. Mechanistically, LEO-mediated regulation of METTL3 decreased AKT1S1 expression by attenuating its mRNA stability. Silencing AKT1S1 inhibited LEO-METTL3 axis-mediated autophagy and enhanced lipid accumulation in ox-LDL-induced macrophages.
The study first revealed that LEO exerts anti-atherosclerotic effect by activating METTL3-mediated macrophage autophagy in vivo and in vitro. The mechanism of LEO was further found to be the enhancement of METTL3-mediated AKT1S1 stability to activate autophagy thereby reducing lipid accumulation. This study provides a new perspective of natural medicines on the treatment of AS via an epigenetic manner.
动脉粥样硬化（AS）是最常见的心血管疾病，仍然是全球死亡和死亡率的主要原因。冬凌草甲素（LEO）是一种独特的生物碱化合物，对心血管系统具有保护作用。然而，其心血管保护作用的确切机制仍未完全阐明。甲基转移酶 3（METTL3）是 N6-甲基腺苷修饰（mA）甲基转移酶复合物的催化核心，已被证明通过调节 mRNA 的 mA 修饰来抑制自噬并加重 AS 进程。
我们旨在确定 LEO 对 AS 的抑制作用是否与 METTL3 介导的 AKT1S1 稳定性有关。
载脂蛋白 E（ApoE）基因敲除小鼠给予高脂饮食（HFD），THP-1 衍生的巨噬细胞暴露于氧化低密度脂蛋白（ox-LDL），分别建立 AS 的动物和细胞模型。
我们发现，LEO 通过减少巨噬细胞脂质积累和重塑脂质代谢谱，有效改善 AS 并降低斑块面积和炎症。通过脂质组学和分子生物学分析，LEO 激活 ox-LDL 诱导的巨噬细胞自噬，增强脂质代谢减少。此外，LEO 在晚期 AS 小鼠模型中显着增加了自噬标志物水平。此外，我们发现 LEO 通过抑制 METTL3 表达来重新激活自噬并逆转脂质积累。ox-LDL 诱导的巨噬细胞中的 mA-seq 显示，总共五种自噬相关 mRNA 转录物（AKT1S1、AKT1、RB1CC1、CFLAR 和 MTMR4）发生改变，LEO 显着上调 AKT1S1。机制上，LEO 介导的 METTL3 调节通过减弱其 mRNA 稳定性来降低 AKT1S1 的表达。沉默 AKT1S1 抑制了 ox-LDL 诱导的巨噬细胞中 LEO-METTL3 轴介导的自噬并增强了脂质积累。
该研究首次揭示，LEO 通过在体内和体外激活 METTL3 介导的巨噬细胞自噬来发挥抗动脉粥样硬化作用。进一步发现，LEO 的作用机制是增强 METTL3 介导的 AKT1S1 稳定性以激活自噬从而减少脂质积累。这项研究提供了一种新的观点，即天然药物通过表观遗传方式治疗 AS。
