Figure 7. A simplified view for M2-type activation in ARF-deficient macrophages. In WT macrophages, a balance between the M1 and M2 phenotype is established, depending on the initiating stimuli. However, ARF-deficient macrophages establish an immunosuppressive and tolerant microenvironment upon the impairment of M1 signals, secretion of the M2 chemokines Ccl17 and Ccl22 as well as of the anti-inflammatory cytokine IL-10, and stimulation of angiogenesis through expression of VEGF and MMP-9. Green and red arrows depict genes that are downregulated and upregulated, respectively, in ARF-deficient macrophages as comparted to their WT counterparts.