Fig. 2.

Effects of adiponectin on macrophage function and phenotype.

Adiponectin suppresses macrophage-to-foam cell transformation via inhibition of class A scavenger receptor (SR-A) expression. Adiponectin reduces expression of M1 macrophage markers including TNF-α, IL-6, MCP-1 and inducible nitric oxide synthase (iNOS), which are involved in activation of NF-κB. Conversely, adiponectin promotes expression of M2 macrophage markers including arginese-1 (Arg-1), IL-10, macrophage galactose N-acetyl-galactosamine specific lectin-1 (Mgl-1) and mannose receptor (MR), contributing to an anti-inflammatory phenotype. Adiponectin can facilitate the phagocytosis of early apoptotic cells by macrophages, which confers the M2 phenotype. Thus, adiponectin promotes the polarization of macrophages towards anti-inflammatory phenotype.