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. 2018 Apr 26;2018:4286364. doi: 10.1155/2018/4286364

Figure 2.

Figure 2

Major signaling pathways involved in M1/M2 polarization. M1 macrophage polarization is mainly induced by granulocyte-macrophage colony-stimulating factor (GM-CSF), interferon (IFN), lipopolysaccharide (LPS), and tumor necrosis factor (TNF), which activate the Janus Kinase/signal transducer and activator of transcription/myeloid differentiation factor 88/nuclear transcription factor-κB (JAK/STAT/MyD88/NF-κB) signaling pathways, which lead to the production of proinflammatory molecules such as inducible nitric oxide synthase (iNOS), TNF-α, interleukin- (IL-) 1, and IL-6. IL-4, IL-10, IL-13, and immune complexes (IC) induce M2 macrophage polarization by activating STAT6 and phosphatidylinositide 3-kinases (PI3K) signaling pathways resulting in the upregulation of peroxisome proliferator-activated receptor- (PPAR-) δ/γ and anti-inflammatory cytokines (IL-10 and tumor growth factor (TGF)-β).