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ALKBH5 Regulates Macrophage Senescence and Accelerates Atherosclerosis by Promoting CCL5 m6A Modification
Rifeng Gao1, Jiaran Shi2, Yang Lyu3
1Department of Cardiac Surgery (R.G., Jianxin Chen, J.J., K.Y.), The Second Affiliated Hospital, Zhejiang University, Hangzhou, China.
Background:
Senescent foamy macrophages are key drivers of atherosclerosis and plaque instability. N6-methyladenosine (m6A) modification of RNA plays an important role in the development of various diseases including aging. Here, we aim to investigate the role of m6A modification of RNA in the formation of senescent foamy macrophages in atherosclerosis.
Methods:
To assess m6A methylation, macrophages were isolated from the atherosclerotic plaques of patients with atherosclerosis, and Apoe-/- mice were fed a high-fat diet using flow cytometry. 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 m6A methylation and increased ALKBH5 expression were observed in arterial plaques and infiltrating macrophages from patients and mice with atherosclerosis. Compared with control mice, ALKBH5f/f, Lyz2Cre, 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 m6A 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 (inhibitor of 2OG oxygenases) 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.
Insights
This study reveals that targeting ALKBH5, CCL5, and CCR5 can reduce senescent foamy macrophages and T cell recruitment, offering new therapeutic strategies for atherosclerosis.
Area of Science:
- Cardiovascular Biology
- Epigenetics
- Immunology
Background:
- Senescent foamy macrophages are critical in driving atherosclerosis and plaque instability.
- RNA N6-methyladenosine (m6A) modification is implicated in aging and disease development.
- Investigating m6A's role in senescent foamy macrophage formation in atherosclerosis is crucial.
Purpose of the Study:
- To investigate the role of m6A RNA modification in the development of senescent foamy macrophages within atherosclerosis.
- To explore the underlying mechanisms of ALKBH5-mediated senescent foamy macrophage formation.
Main Methods:
- Macrophages from human atherosclerotic plaques and Apoe mice on a high-fat diet were analyzed using flow cytometry.
- An ALKBH5, Lyz2, Apoe mouse model was utilized to assess plaque progression and senescent foamy macrophage infiltration.
- Techniques including methylated RNA immunoprecipitation, RNA immunoprecipitation sequencing, and dual-luciferase assays were employed.
Main Results:
- Decreased m6A methylation and elevated ALKBH5 expression were observed in atherosclerotic plaques and macrophages.
- ALKBH5 deletion in mice reduced plaque burden and increased stability by suppressing senescent foamy macrophage formation.
- ALKBH5 deletion decreased CCL5 mRNA stability via increased m6A methylation, impacting the CCL5/CCR5/autophagy pathway and CD8+ T cell recruitment.
Conclusions:
- Myeloid ALKBH5 deletion mitigates atherosclerosis by inhibiting senescent foamy macrophage formation and CD8+ T cell infiltration.
- ALKBH5, CCL5, and CCR5 represent promising novel therapeutic targets for atherosclerosis treatment.
- Inhibitors like IOX1 and maraviroc show potential for clinical intervention against atherosclerosis progression.
