Epigenetic modification of TWIST1 in macrophages promotes hypertension-induced atherosclerotic plaque instability

It is accepted that hypertension is a major, independent risk factor for atherosclerotic cardiovascular ischemic events, which are mainly attributed to the formation of unstable, vulnerable atherosclerotic lesions. But the mechanisms by which hypertension aggravates atherosclerosis (AS) through increased macrophage recruitment are unknown. It has been reported that TWIST1 can regulate the shear stress of blood flow in endothelial cells to promote the development of atherosclerosis, but the function of TWIST1 in macrophage recruitment during hypertension remains undefined. Here, the roles of TWIST1 in macrophage activation during N ^w -nitro-l-arginine-methyl ester (L-NAME; NO-synthase (NOS) inhibitor)-induced hypertension were investigated in ApoE^-/- mice fed a high-fat diet (HFD) and RAW264.7 cells treated with oxidized low-density lipoprotein(ox-LDL). Oil Red O staining and hematoxylin and eosin staining were adopted to analyze atherosclerotic lesions and plaque instability. Chromatin immunoprecipitation (ChIP)-PCR was used to explore whether Lysine-specific Histone Demethylase 1A (LSD1/KDM1A) and Variegated suppressor 3-9 homolog 1 (SUV39H1) could regulate histone modification of the TWIST1 promoter. We reported that L-NAME increased the expression of TWIST1 in the aortic tissues of ApoE^-/- mice fed a high-fat diet (HFD) and RAW264.7 cells treated with ox-LDL. TWIST1 accelerated the development of an unstable atherosclerotic phenotype by promoting macrophage activation, inflammatory factor secretion, macrophage polarization, and lipid phagocytosis. Moreover, we found that H3K9me2 and H3K9me3 in the TWIST1 promoter could be coregulated by LSD1 and SUV39H1, and this process was modulated by CK2α. Taken together, these results revealed that TWIST1 in macrophages is a critical factor that mediates foam cell formation and enhances atherosclerotic plaque vulnerability during hypertension, and targeting TWIST1 may be a promising new therapeutic approach for delaying the progression of AS in hypertension.

Atherosclerotic plaque stability; Histone methylation and demethylation; Hypertension; Macrophage phenotype; TWIST1.