ITGAM induced macrophage M2 polarization through activating FAK/Akt1/β-catenin signaling
The mechanism that ITGAM mediated M2 polarization in macrophage was verified by silencing Itgam mRNA, and inhibiting FAK and Akt1 phosphorylation (Figure 5A ). As shown by pre-experiment, we picked the Itgam siRNA with the highest knockdown efficiency (mean difference = 77.6%, Supplementary Figure 3 ). After knocking down Itgam, we observed the decreased phosphorylation of FAK and Akt1, and reversed the upregulation of phosphorylated GSK-3β, together with downregulation of β-catenin protein (Figure 5B ). Meanwhile, M2 polarization was greatly attenuated after Itgam knockdown, indicated by significant decrease in Arg1, Mr, Fizz1, and Ym1 mRNA expression (Figure 5C ). Similar effects were found after FAK and Akt1 intervention. After inhibiting phosphorylation of these two proteins, the downstream signaling was significantly suppressed together with reduced M2 polarization (Figures 5D-G ).