Macrophage origin, phenotypic diversity, and modulatory signaling pathways in the atherosclerotic plaque microenvironment

Abstract

Atherosclerosis is the main pathological basis of most cardiovascular diseases and the leading health threat in the world. Of note, lipid-lowering therapy cannot completely retard atherosclerosis progression, even in patients treated with combined statins and PCSK9 inhibitors. This failure further impels researchers to explore other underlying therapeutic strategies except for lipid-lowering. Monocytes and macrophages are the major immune cell groups in atherosclerotic plaques. They play important roles in all stages of atherosclerosis, including the occurrence, advance, and regression. It is interesting that macrophages are demonstrated to have plastic and heterogenous characteristics within the dynamic atherosclerotic plaque microenvironment. Furthermore, the phenotype of macrophages can switch upon different microenvironmental stimulus. Therefore, macrophages have become a potential therapeutic target for anti-atherosclerosis treatment. This article reviews the phenotypic diversity of macrophages and their roles in dynamic atherosclerotic plaque microenvironment, especially the related signaling pathways involved in macrophage polarization and compounds exhibiting therapeutic effects.