Macrophage Polarization in Chronic Inflammatory Diseases: Killers or Builders?

Figure 1

Past and new concept in macrophage polarization. (a) Schematic overview of the different stimuli that can induce the diverse macrophage polarization state. M1: classically activated phenotype; M2: alternatively activated macrophages; ATM: adipose tissue-derived macrophages; Mox: atherosclerosis-associated macrophages; TAMs: tumour-associated macrophages. (b) The polarization landscape of macrophages. According to the different stimulation conditions, macrophages can acquire peculiar M1 or M2 phenotype, governed by the different surface antigen expressions, including scavenger receptors, chemokine, matrix-associated protein and cytokine release, and different patterns of transcription factors and metabolic pathway activated. The driver stimuli include IL-4, IL-10, glucocorticoids (GC) with TGF-β, glucocorticoids alone, LPS, LPS and IFN-γ, and IFN-γ alone.

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