S184 Poster presentations P097 Depletion of delta-like ligand 4 (Dll4) contributes to the alteration of secretory progenitor differentiation in SAMP1/YitFc mice with Crohn’s disease-like ileitis S.N. Hong* 1 , J.H. Song 2 , G. Seong 1 , S.M. Kong 1 , J.B. Shin 1 , K. Eun Ran 1 , C. Dong Kyung 1 , K. Young-Ho 1 1 Samsung Medical Center, Department of Gastroenterology, Seoul, Republic of Korea, 2 Samsung Medical Center, Gastroenterology, Seoul, Republic of Korea Background: When the intestinal epithelium would be exposed to harmful substances, mucosal damage can be occurred and followed by epithelial restoration with regenerative epithelium derived from intestinal stem cells (ISCs). Crohn’s disease (CD) is characterised by chronic mucosal damage and ulceration predominantly involved in the ileum. Thus, we hypothesised that epithelial regeneration in CD might be impaired due to the dysfunction of ileal ISCs or its niche. Methods: SAMP1/YitFcsI (SAMP1) mice are recombinant-inbred mice that spontaneously develop ileitis resembling human CD. Alterations in the crypt-villus structure, epithelial differentiation, organoid formation ability, and niche signalling pathways in the ileum of 10- to 14-week-old SAMP1 mice were analysed and com- pared with age-matched AKR mice. Results: In the ileum of SAMP1 mice, the depth of the crypts increased and the surface area of the villi decreased. While the number of ISCs in the ileal crypts did not differ between SAMP1 and AKR mice. The number of Paneth cells decreased and the number of transient amplifying cells increased. The organoid formation ability of the ileal crypts of SAMP1 mice decreased signifcantly compared with that of AKR mice. RNA-seq revealed a differential gene expres- sion pattern of ileal crypts of SAMP1 mice compared with those of AKR mice. Among the ISCs and niche signalling, the expression of delta-like ligand 4 (Dll4) was signifcantly decreased and the expres- sion of genes associated with Notch signalling tended to decrease in the ileal crypts of SAMP1 mice. Conclusion: The characteristic ileitis in SAMP1 mice may be caused by impaired Dll4-Notch signalling. P098 Receptor-interacting protein 1 kinase inhibition therapeutically ameliorates experimental T-cell- dependent colitis in mice T. Gobbetti* 1 , F. Kathryn 1 , A. Beal 2 , A. Rowles 3 , G. Pearse 4 , I. Harada 5 , J. Bertin 2 , A. Haynes 1 , S. Berger 2 1 GSK, Adaptive Immunity Research Unit, Stevenage, UK, 2 GSK, Innate Immunity Research Unit, Philadelphia, USA, 3 GSK, In Vitro/ In Vivo Translation, Ware, UK, 4 GSK, 3In Vitro/In Vivo Translation, Ware, UK, 5 GSK, Dmpk, Stevenage, UK Background: Infammatory bowel disease (IBD) is a multifactorial disorder characterised by chronic and relapsing intestinal infamma- tion. Receptor-interacting protein 1 (RIP1) kinase activity is emerg- ing as a driver of pro-infammatory cytokine production and cell death and has been implicated in multiple infammatory diseases including IBD. To this end, recent work has shown that RIP1 kinase inhibition reduces the spontaneous production of cytokines from human ulcerative colitis (UC) and Crohn’s disease explants. Methods: The aim of this study was to investigate the anti-infam- matory effect of a highly selective inhibitor of RIP1 kinase activity (GSK547A) in the mouse T-cell transfer model of colitis; a model that shares many features with human IBD. All animal studies were ethically reviewed and carried out in accordance with Animals (Scientifc Procedures) Act 1986 and the GSK Policy on the Care, Welfare and Treatment of Animals. Chronic colitis was achieved by transferring CD4 + CD45RB high T cells into immunodefcient female SCID mice (6/8 weeks old). After confrming the development of pathology using endoscopy and MRI, animals were treated thera- peutically with the RIP1 inhibitor GSK547A (50 mg/kg twice a day PO) or vehicle (0.5% hydroxypropyl methylcellulose in water). The severity of colitis was measured 5 weeks after cell transfer both macro- and microscopically. Mucosal damage by endoscopy was also assessed. RT-PCR and MSD analysis were performed to detect colon cytokine/chemokine and calprotectin levels. SAA in the plasma was measured using ELISA. Results: We found that treatment with GSK547 signifcantly ame- liorated experimental T-cell-dependent colitis in mice. GSK547A- treated mice displayed decreased weight loss, colon density (ratio weight/length), macroscopic disease activity index, colon thickness compared with vehicle-treated animals. Mucosal damage, assessed by endoscopy and histopathology, was also reduced following treat- ment with RIP1 kinase inhibitor. In addition, GSK547A reduced the expression of cytokines in the colon (TNF-α, IL-17A, INF-γ, IL-6 and MCP-1), both at a protein and RNA level. Relevant transla- tional biomarkers such as SAA in plasma and RNA calprotectin in the colon were also decreased in the GSK547A treated group when compared with vehicle. Conclusion: Our results suggest that RIP1K inhibition is a strong protective factor with anti-infammatory potential in the progres- sion of chronic colitis, when applied to the translationally relevant T-cell transfer model of colitis. These fndings suggest the potential application in the management of infammatory bowel disease and support the ongoing clinical program evaluating the effect of RIP1 kinase inhibition in UC patients. P099 Neutrophil gelatinase-associated lipocalin (NGAL) as biomarker in collagenous colitis G.A. Walaas* 1 , I. Bakke 1,2 , A.V. Granlund 1,3 , C. Escuderos-Hernândez 4 , T. Bruland 1,2 , E.S. Røyset 1,5 , S. Thorsvik 2,6 , A. Münch 4,7 , A.E. Østvik 1,2,6 , A.K. Sandvik 1,2,3,6 1 Norwegian University of Science and Technology, Department of Clinical and Molecular Medicine, Faculty of Medicine and Health Sciences, Trondheim, Norway, 2 St. Olav’s University Hospital, Clinic of Medicine, Trondheim, Norway, 3 Norwegian University of Science and Technology, Centre of Molecular Infammation Research, NTNU, Trondheim, Norway, 4 Linköping University, Department of Biomedical and Clinical Sciences BVK, Linköping, Sweden, 5 St. Olav’s University Hospital, Department of Pathology, Clinic of Laboratory Medicine, Trondheim, Norway, 6 St. Olav’s University Hospital, Department of Gastroenterology, Clinic of Medicine-, Trondheim, Norway, 7 Linköping University Hospital, Department of Gastroenterology and Hepatology, Linköping, Sweden Background: Neutrophil gelatinase‐associated lipocalin (NGAL) is upregulated in the intestinal epithelium in infammatory bowel disease and is a biomarker with sensitivity and specifcity Downloaded from https://academic.oup.com/ecco-jcc/article/14/Supplement_1/S184/5705437 by guest on 02 January 2024