Fig. 6

Cytokines IL-10 positive feedback induces macrophage M2 polarization and upregulates macrophage-derived CXCL8 expression. A IL-10 promoted macrophages CD163 expression and induced M2 polarization. B IL-10 activated NF-κB signaling pathway. C The NF-κB pathway inhibitor (Sarsasapogenin) could limit IL-10 induced M2 polarization. D E. IL-10 upregulated CXCL8 expression, and it could be prevented by NF-κB pathway inhibitor. F. IL-10 could promote CXCL8 secretion, and Sarsasapogenin could antagonize the effect of IL-10. G Deletion and selective mutation analysis recognized the NFKB1-responsive regions in the CXCL8 promoter. Luciferase reporter plasmids containing serially truncated or mutated CXCL8 promoter constructs were co-transfected with OE-NFKB1 into macrophage cells, and relative luciferase activities were detected. The − 1829 ~ − 1819 and − 91 ~ − 81 sequences were all the binding sites