Skip to main content
. 2021 Aug 20;22(16):8992. doi: 10.3390/ijms22168992

Figure 2.

Figure 2

Macrophage intracellular reprogramming during polarization. Balanced switching of M1/M2 macrophage action is crucial. Both the HIF-1α and HIF-2α subunits are essential to maintain the NF-κB level. However, due to the incongruent roles of HIF-2α, the part of the phenotypic switch between HIF-1α and HIF-2α in M1/M2 macrophages remains uncertain. M1 macrophage polarization is NF-κB-independent. NF-κB mediates the IkBζ recruitment to target promoter and acts as a transcriptional coactivator for chromatin remodeling that regulates the CCL2 (MCP-1) gene, thus producing cytokines such as TNF-α, IL-1β, IL-6, IL-12, and IFN-γ. M2 macrophages upon IL-4 stimulation activate STAT6, which then induces PGC-1β that is essential for the M2 macrophage profile and is characterized by IL-10 and TGF-β1 expression. Meanwhile, Jmjd-3, a histone 3 Lys27 (H3K27) demethylase that directly targets IRF-4, is crucial for M2 macrophages.