Moreover, peritoneal macrophages derived from ApoE−/−Nr4a1−/− mice in an atherosclerosis mouse model showed enhanced levels of IL-12, iNOS, and major histocompatibility complex II (MHCII) compared to ApoE−/− peritoneal macrophages, supporting the notion that the absence of Nr4a1 increases macrophage activation in atherosclerosis [3]. Here, APOE is linked to atherosclerosis.