When injected intraperitoneally into 20 week old Western diet-induced obese wild-type C57BL/6 mice and LDL receptor-deficient Apoeh/h Ldlr−/− mice, THP1 Mφ-IL-4 exosomes suppressed systemic inflammation, VAT and hepatic inflammation (F4/80+ CLS formation), aortic inflammation (atherosclerosis), inflammatory markers of M1 macrophages (Tnf, Il1b, Mcp1, and Nos2), hepatocyte lipid accumulation, and hepatic steatosis and substantially reduced NF-κB activation, mitochondrial oxidative stress (superoxide production), fasting glucose, and insulin levels. The gene discussed is CCL2; the disease is fatty liver disease.