NINJ1 and atherosclerosis: As a substrate of matrix metalloproteinase 9, macrophage NINJ1 is directly cleaved by matrix metalloproteinase 9 to generate a soluble form, which reduces the expression of proinflammatory genes in human and mouse classically activated macrophages, thereby attenuating monocyte transendothelial migration and alleviating atherosclerosis (76).