Tu1270 IN VITRO HUMAN ORGANOIDS COLITIS MODEL REVEALS A NOVEL TARGET FOR MUCOSAL HEALING IN ULCERATIVE COLITIS.

Background: Ulcerative Colitis (UC) causes chronic inflammation and ulceration.Recently, mucosal healing becomes a therapeutic goal of UC because dysfunction of epithelial cells might cause frequent relapse.Certainly, we have reported that mice colonic organoids were transformed to UC like cells by long-term inflammatory stimulation.Even though, the pathogenesis of epithelial cells in UC patients remains unknown.We therefore aimed to establish the chronic inflammation model of human colonic organoids which mimic the pathogenesis of UC and reveal new treatment targets specific to colonic epithelium for mucosal healing.Methods: Human colonic organoids were established from normal mucosa of 3 different people by endoscopic biopsy.Organoids were cultured more than 60weeks with or without inflammatory reagents as we previously reported.Inflammatory response was confirmed with NFkB signal and ROS production.MTS, sphere formation and apoptosis assay were performed to access the phenotype of organoids.Xenotransplantation of human organoids into mice colon was performed to access the histological changes by chronic inflammation.New treatment target genes for chronic inflammation were extracted by microarray analysis.The function of target was confirmed with shRNA based analysis.Results: We have established the chronic inflammation model of human colon organoids.This model revealed that chronic inflammation induced apoptosis and attenuated cell proliferation and sphere formation.Moreover, these phenotypic changes were irreversible after 10weeks from removal of inflammation.These set of findings were also confirmed with GSEA analysis of microarray sample.Furthermore, chronic inflammation model mimicked the organoids derived from UC patients in the phenotypes and gene expression level.Additionally, pathological changes of human crypt by chronic inflammation were found in xenotransplanted mucosa.Microarray analysis also revealed several chronic inflammation specific markers but not elevated in acute phase, including SOBP, TMEM45A, SLFN11.SLFN11 were highly expressed in colonic epithelium of UC patient's.shRNA analysis of SLFN11 showed the resistance of human colonic organoids to chronic inflammation such as promotion of stemness, cell proliferation and anti-apoptosis.Conclusion: We for the first time established the human UC model in vitro which is useful to understand the pathogenesis of UC.This model also revealed novel treatment targets of the colonic epithelium of UC patients.Especially, SLFN11 would be a candidate of treatment for mucosal healing. Tu1271