Fig. 7

Increased FCN1⁺ macrophage infiltration promotes intestinal inflammation in PIBD. A Diagram showing the standardized methods to induce the differentiation of THP-1 cells into M0, M1 and M2 type populations of macrophages. B Western blot analysis of M0, M1 and M2 macrophages derived from THP-1 cells. C Diagram of transfection and stimulation of THP-1 cells. D Western blot analysis of THP-1 cells with different treatments as described in C. FCN1-OE: FCN1-overexpression. E The mechanistic diagram of FCN1 function in PIBD. FCN1⁺ macrophage infiltration is increased in the colonic mucosa of PIBD. Impaired intestinal mucosal barrier in PIBD leads to translocation of bacteria and bacterial components such as LPS, and FCN1⁺ macrophages are exposed to LPS. Macrophage FCN1 promotes LPS-induced activation of the proinflammatory cytokine IL-1β via NLRP3-dependent cleavage of caspase-1, resulting in increased intestinal inflammation