Inflammatory bowel disease, which typically manifests as Crohn's disease and ulcerative colitis, is caused by the abnormal production of cytokines such as tumor necrosis factor (TNF)-α and transforming growth factor (TGF)-β. These cytokines damage intestinal epithelial cells and trigger fibrosis, respectively, for which the current in vitro models have many limitations. Therefore, we tested whether human induced pluripotent stem cell-derived intestinal organoids (HiOs) can mimic inflammatory bowel disease (IBD), and whether such a model is suitable for drug screening. HiOs were treated with TNF-α and TGF-β to construct mucosal damage and fibrosis models. TNF-α diminished the mRNA expression of intestinal epithelial cell and goblet cell markers in HiOs. TNF-α also induced epithelial cell damage and degradation of tight junctions but not in the presence of infliximab, an antibody used in the clinic to deplete TNF-α. Furthermore, permeation of the non-absorbable marker FD-4 was observed in HiOs treated with TNF-α or ethylene glycol tetraacetic acid (EGTA), but not in the presence of infliximab. In contrast, TNF-α and TGF-β induced mRNA expression of mesenchymal and fibrosis markers, as well as epithelial-mesenchymal transition. SB431542, a TGF-β inhibitor, significantly reversed these events. The data indicate that HiOs mimic mucosal damage and fibrosis due to IBD and are thus suitable models for drug screening.
Keywords: induced pluripotent stem cell; inflammatory bowel disease; intestinal organoid; transforming growth factor (TGF)-β; tumor necrosis factor (TNF)-α.