VCAM-1 knockdown in macrophages reduces inflammation in atherosclerosis. ApoE^−/− mice on high fat diet were injected with control siRNA (siCON) or VCAM-1–targeting siRNA (siVCAM-1) for 3 wk. (A) Macrophages and monocytes in the aorta (n = 5–6). Apoptosis and proliferation (B–E) of plaque macrophages by flow cytometry (B and C) and immunofluorescence (D and E; n = 5). (F) mRNA of netrin-1 and CCR7 in the aortic root (n = 4–5). (G) LSK and HSC levels in the spleen of siCON and siVCAM-1-treated ApoE^−/− mice (n = 5). Monocyte and inflammatory (Ly-6c^high) monocyte levels in the spleen (H) and blood (I; n = 5–6). (J) Masson staining of the aortic root showing plaque size and necrotic core area (n = 5). Bar, 30 µm. (K) Blood cholesterol in ApoE^−/− mice (n = 6). Data were pooled from at least two experiments and are shown as mean ± SEM. Significance was determined by Mann-Whitney test. *, P < 0.05; **, P < 0.01.