MAT2A promotes atherosclerotic plaque vulnerability by mediating epigenetic reprogramming of macrophages

Atherosclerosis is mediated by circulating monocytes and lesional macrophages through chronic inflammation accompanied by metabolic reprogramming. Although methionine metabolism enhances the proinflammatory capacity of monocytes/macrophages, its role in atherosclerosis remains unclear. Here, we use untargeted metabolomics and mass spectrometry to demonstrate that monocyte methionine metabolism is associated with vulnerable plaque (thin-cap fibroatheroma [TCFA]) identified by pancoronary optical coherence tomography. Methionine adenosyltransferase Ⅱ alpha (MAT2A), the key enzyme of methionine metabolism, is highly expressed in atherosclerosis. Further epigenetic profiling of inflammatory and migratory gene promoters reveals MAT2A-mediated enrichment of the transcriptional permissive chromatin mark H3K4me3. Myeloid-specific MAT2A ablation and pharmacological inhibition, or a low-methionine diet, reduce monocyte/macrophage inflammation and migration, thereby attenuating plaque vulnerability. Mechanistically, norepinephrine activates the mTOR-c-MYC axis to upregulate MAT2A expression. The combination of norepinephrine and methionine metabolism is associated with TCFA presence and 5-year clinical prognosis. Consequently, MAT2A-mediated methionine metabolism represents a potential therapeutic target for atherosclerosis. Monocytes/macrophages exert pro-atherogenic functions depending on their metabolic programming. Here, the authors show the pivotal role of methionine metabolism in the proinflammatory and migratory functions of monocytes/macrophages and identify MAT2A as a potential target for the management of atherosclerosis.