Fig. 8

Schematic model of the proposed mechanism underlying the role of IL-24 in the IBD-associated tissue remodeling. Our results showed increased amount of IL-24 in the inflamed colonic mucosa of IBD patients or DSS treated mice. IBD-related factors, including IL-1ß, LPS or H₂O₂ are direct inducers of IL-24 in immune cells derived from lamina propria (LPMCs) or peripheral blood (PBMCs). IL-24 enhances the synthesis of pro-fibrotic factors, including TGF-β and PDGF-B in epithelial cells. These growth factors together with IL-24 induce the activation of colonic fibroblast leading to the excessive deposition of extracellular matrix (ECM) components