ALKBH5 Regulates Macrophage Senescence and Accelerates Atherosclerosis by Promoting CCL5 m 6 A Modification

BACKGROUND: Senescent foamy macrophages are key drivers of atherosclerosis and plaque instability. N 6 -methyladenosine (m 6 A) modification of RNA plays an important role in the development of various diseases including aging. Here, we aim to investigate the role of m 6 A modification of RNA in the formation of senescent foamy macrophages in atherosclerosis. METHODS: To assess m 6 A methylation, macrophages were isolated from the atherosclerotic plaques of patients with atherosclerosis, and Apoe −/− mice were fed a high-fat diet using CD68 + magnetic beads. An ALKBH5 (alkB homolog 5) f/f , Lyz2 (lysozyme 2) Cre , Apoe −/− mouse model was generated to determine the infiltration of senescent foamy macrophages into plaques and atherosclerosis progression. Methylated RNA immunoprecipitation, RNA immunoprecipitation sequencing, and dual-luciferase assays were performed to explore the mechanisms underlying the ALKBH5-mediated formation of senescent foamy macrophages. RESULTS: Decreased m 6 A methylation and increased ALKBH5 expression were observed in arterial plaques and infiltrating macrophages from patients and mice with atherosclerosis. Compared with control mice, ALKBH5 f/f , Lyz2 Cre , Apoe −/− mice exhibited fewer atherosclerosis plaques with greater stability, which was attributed to the suppression of senescent foamy macrophage formation and senescence-associated secretory phenotype. In addition, ALKBH5 deletion reduced the mRNA expression level of CCL5 (CC chemokine ligand 5) by increasing m 6 A methylation in macrophages, which disrupts the stability of CCL5 mRNA. Mechanistically, ALKBH5 promoted senescent foamy macrophage formation through the CCL5/CCR5 (CC chemokine receptor 5)/autophagy signaling pathway. CCL5 also recruited CD8 + IFN (interferon)γ + T cells via the CCL5-CCR5 axis. The ALKBH5 inhibitor IOX1 and the CCR5 antagonist maraviroc were identified as potential clinical interventions for inhibiting senescent foamy macrophage formation and atherosclerosis progression. CONCLUSIONS: Myeloid ALKBH5 deletion attenuates atherosclerosis progression by suppressing the formation of senescent foamy macrophages and the recruitment of CD8 + IFNγ + T cells. These findings identify ALKBH5, CCL5, and CCR5 as novel therapeutic targets for atherosclerosis.