Macrophage METTL3 synergizes with YTHDF2 to promote atherosclerosis by inhibiting the LXR-α/ABCA1 pathway.

BACKGROUND AND AIM: The formation of subendothelial macrophage-derived foam cells is a key driver of atherogenesis and contributes to the onset and progression of atherosclerosis (AS). The METTL3 gene, a central mediator of N6-methyladenosine (m6A) RNA methylation, serves as a critical regulatory node at the inflammation-metabolism nexus in immune pathophysiology.

METHODS AND RESULT: This study aimed to investigate the METTL3-mediated regulatory mechanisms in subendothelial macrophage-derived foam cells formation and their association with necrosis and the pro-inflammatory properties of AS lesions. METTL3 expression was significantly higher in human carotid artery plaques compared to non-plaques. Macrophages treated with ox-LDL had an upregulated METTL3 expression, while its knockdown reduced lipid accumulation, foam cell formation, and inflammatory responses in macrophages. Myeloid Mettl3 knockout AS mice exhibited attenuated AS lesions. METTL3 knockdown elevated ABCA1, LXR-α, and ZNF771 expression. Gain- and loss-of-function studies demonstrated that METTL3 modulates lipid accumulation and inflammation partly through the ZNF771/LXR-α/ABCA1 axis. YTHDF2 knockdown increased ZNF771 levels, indicating that METTL3 cooperates with YTHDF2 to suppress ZNF771 expression, thereby inhibiting LXR-α transcription. Macrophage METTL3 exacerbates AS by suppressing cholesterol efflux and amplifying inflammation through YTHDF2-mediated downregulation of ZNF771, which attenuates the LXR-α/ABCA1 axis.

CONCLUSIONS: Our study identifies a novel METTL3-dependent mechanistic link between foam cell pathology and plaque destabilization.