Macrophage MCT4 inhibition activates reparative genes and protects from atherosclerosis by histone H3 lysine 18 lactylation

Macrophage activation is a hallmark of atherosclerosis, accompanied by a switch in core metabolism from oxidative phosphorylation to glycolysis. The crosstalk between metabolic rewiring and epigenetic modifications in macrophages is worthy of further investigation. Here, we found that lactate efflux-associated monocarboxylate transporter 4 (MCT4)-mediated histone lactylation is closely related to atherosclerosis. Histone H3 lysine 18 lactylation dependent on MCT4 deficiency activated the transcription of anti-inflammatory genes and tricarboxylic acid cycle genes, resulting in the initiation of local repair and homeostasis. Strikingly, histone lactylation is characteristically involved in the stage-specific local repair process during M1 to M2 transformation, whereas histone methylation and acetylation are not. Gene manipulation and protein hydrolysis-targeted chimerism (PROTAC) technology were used to confirm that MCT4 deficiency favors ameliorating atherosclerosis. Therefore, our study shows that macrophage MCT4 deficiency, which links metabolic rewiring and epigenetic remodeling, plays a key role in training macrophages to become repair and homeostasis phenotypes. ox-LDL-induced THP-1-derived macrophages with or without MCT4 deficiency, three samples for each group.