Division of Cardiothoracic and Vascular Surgery, Sino-Swiss Heart-Lung Transplantation Institute, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China.
Cardiac Rehabilitation Center, Fuwai Hospital CAMS&PUMC, Beijing, China.
Cell Prolif. 2023 Apr;56(4):e13386. doi: 10.1111/cpr.13386. Epub 2022 Dec 23.
Prevention of neointima formation is the key to improving long-term outcomes after stenting or coronary artery bypass grafting. RNA N -methyladenosine (m A) methylation has been reported to be involved in the development of various cardiovascular diseases, but whether it has a regulatory effect on neointima formation is unknown. Herein, we revealed that methyltransferase-like 3 (METTL3), the major methyltransferase of m A methylation, was downregulated during vascular smooth muscle cell (VSMC) proliferation and neointima formation. Knockdown of METTL3 facilitated, while overexpression of METTL3 suppressed the proliferation of human aortic smooth muscle cells (HASMCs) by arresting HASMCs at G2/M checkpoint and the phosphorylation of CDC2 (p-CDC2) was inactivated by METTL3. On the other hand, the migration and synthetic phenotype of HASMCs were enhanced by METTL3 knockdown, but inhibited by METTL3 overexpression. The protein levels of matrix metalloproteinase 2 (MMP2), MMP7 and MMP9 were reduced, while the expression level of tissue inhibitor of metalloproteinase 3 was increased in HASMCs with METTL3 overexpression. Moreover, METTL3 promoted the autophagosome formation by upregulating the expression of ATG5 (autophagy-related 5) and ATG7. Knockdown of either ATG5 or ATG7 largely reversed the regulatory effects of METTL3 overexpression on phenotypic switching of HASMCs, as evidenced by increased proliferation and migration, and predisposed to synthetic phenotype. These results indicate that METTL3 inhibits the phenotypic switching of VSMCs by positively regulating ATG5-mediated and ATG7-mediated autophagosome formation. Thus, enhancing the level of RNA m A or the formation of autophagosomes is the promising strategy to delay neointima formation.
抑制新生内膜形成是改善支架置入或冠状动脉旁路移植术后长期预后的关键。RNA N -甲基腺苷（m A）甲基化已被报道参与多种心血管疾病的发生，但它是否对新生内膜形成有调节作用尚不清楚。在此，我们揭示了甲基转移酶样蛋白 3（METTL3），即 m A 甲基化的主要甲基转移酶，在血管平滑肌细胞（VSMC）增殖和新生内膜形成过程中下调。METTL3 的敲低促进了人主动脉平滑肌细胞（HASMC）的增殖，而 METTL3 的过表达则通过将 HASMC 阻滞在 G2/M 检查点并使 CDC2 磷酸化（p-CDC2）失活来抑制 HASMC 的增殖。另一方面，METTL3 的敲低增强了 HASMC 的迁移和合成表型，而 METTL3 的过表达则抑制了其迁移和合成表型。MMP2、MMP7 和 MMP9 的蛋白水平降低，而 HASMC 中 METTL3 的过表达增加了组织金属蛋白酶抑制剂 3 的表达水平。此外，METTL3 通过上调 ATG5（自噬相关蛋白 5）和 ATG7 的表达促进自噬体的形成。ATG5 或 ATG7 的敲低在很大程度上逆转了 METTL3 过表达对 HASMC 表型转换的调节作用，表现在增殖和迁移增加，并倾向于合成表型。这些结果表明，METTL3 通过正向调节 ATG5 介导和 ATG7 介导的自噬体形成来抑制 VSMC 的表型转换。因此，提高 RNA m A 的水平或自噬体的形成可能是延迟新生内膜形成的有前途的策略。
