CD9 and atherosclerosis: In previous single-cell studies on atherosclerosis, various macrophage subtypes have been identified, including TREM2hi Mφ (high expression of Abcg1, Trem2, Fabp4, Cd9, Spp1, Mmp12, and Mmp14), SMC-derived Mφ (Klf4, Cd68, Lgal3), Proliferative Mφ (Mki67, Birc5, and Stmn1), inflammatory Mφ (Cxcl2, Ccl3, Ccl4, Il1β, and Tnf), Adventitia resident (Lyve1, Mrc1, Cx3cr1, Pf4, and Folr2), and IFN-inducible (Irf7, Ifitm3, Isg15, and Ifit2)27,65,66.