What question did this study set out to answer?

The research aims to explore how epithelial endoplasmic reticulum stress contributes to fibrosis in ulcerative colitis, independent of inflammation.

January 23, 2026

P0137Apical-Out Organoids Derived from UC Patients as a Model to Investigate Epithelial ER Stress-Induced Fibrosis Independent of Inflammation

Key Points

The research aims to explore how epithelial endoplasmic reticulum stress contributes to fibrosis in ulcerative colitis, independent of inflammation.
Deriving apical-out organoids from intestinal stem cells of 12 UC patients.
Inducing transient ER stress using Tunicamycin (Tm).
Analyzing cellular fractions, supernatants, and performing ELISA for active eAGR2 measurement.
Conducting bulk transcriptomic analysis to investigate molecular changes.
Increased ER stress markers were observed in organoids (fold change for BiP/CHOP/sXBP1 6-20, 4-28, 3-8).
No significant changes in pro-inflammatory or pro-fibrotic cytokines were noted compared to controls.
AGR2 expression exhibited a median fold change of 7.57 post-ERS induction.
Active eAGR2 levels in supernatants increased with a median fold change of 1.77 after ER stress induction.
Induction of CCD18-Co with collected supernatants showed a 44 to 120% increase in α-SMA signal, confirming fibroblast-to-myofibroblast transition.

Abstract

Abstract Background Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) with diffuse colonic mucosal inflammation. Fibrosis which has been observed in the submucosa and muscularis mucosae even without active inflammation1, yet remains underexplored in UC. No anti-fibrotic treatments have been proven clinically efficient to cure fibrosis in IBD. At the epithelial level, IBD-related endoplasmic reticulum stress (ERS) and inflammation upregulate ER chaperones like AGR2, which, when secreted (eAGR2), can induce fibroblast-to-myofibroblast transition (FMT) suggesting a role for eAGR2 in fibrosis2. Beside eAGR2 other factor might be released by stressed epithelium and drive fibrosis progression. Our aim is to use a pro-fibrotic organoid model challenged by transient ERS induction without inflammation drivers to study the epithelium’s contribution to UC fibrosis Methods Apical-out organoids3 were derived from intestinal stem cells of 12 UC patients and submitted to transient4 ERS with Tunicamycin (Tm). We collected cellular fractions and supernatant after a recovery period in fresh medium for molecular characterisation of the changes driven by this stress and assessed their positive FMT paracrine effects on CCD18-Co as in Vieujean et al 2. RNA, protein, and supernatants were analyzed for ERS markers, epithelial-mesenchymal transition (EMT), pro-fibrotic and inflammatory cytokines evaluations. The active eAGR2 was quantified by ELISA in supernatants. We also conducted a bulk transcriptomic analysis to confirm the biomolecular patterns and investigate the complete molecular changes characterizing this epithelial profibrotic phenotype Results Organoids from UC patients showed increased ERS markers (RT-qPCR: BiP/CHOP/sXBP1 fold change 6-20, 4-28, and 3-8), with no significant variation in pro-inflammatory cytokines or pro-fibrotic. AGR2 expression increased post-ERS compared to vehicle (fold change median: 7,57). Intracellular AGR2, BiP, and ERP72 rose in parallel with ERS induction. Active eAGR2 levels measured by ELISA in supernatants statistically increased post-ERS (Tm/CTL eAGR2 median fold change:1,77). CCD18-Co induced with supernatants showed elevated α-SMA signal (44 to 120% more intense in Tm cdt), confirming FMT. ERS biomolecular targets were statistically confirmed by Dseq2 differential transcriptomic analysis and GSEA Conclusion We studied the ERS-induced epithelial responses of organoids derived from UC patients and showed their pro-fibrogenic effect on FMT, independently of pro-inflammatory drivers suggesting that epithelial ERS response alone may promote UC intestinal fibrosis. The specific role of eAGR2 and other molecular changes characterising this phenotype is under further investigation including the paracrine factors References: 1)Gordon IO, Agrawal N, Willis E, et al. Fibrosis in ulcerative colitis is directly linked to severity and chronicity of mucosal inflammation. Aliment Pharmacol Ther. 2018;47(7):922-939. doi:10.1111/apt.14526 2)Vieujean S, Hu S, Bequet E, et al. Potential Role of Epithelial Endoplasmic Reticulum Stress and Anterior Gradient Protein 2 Homologue in Crohn’s Disease Fibrosis. J Crohns Colitis. 2021;15(10):1737-1750. doi:10.1093/ecco-jcc/jjab061 3)Co JY, Margalef-Català M, Monack DM, Amieva MR. Controlling the polarity of human gastrointestinal organoids to investigate epithelial biology and infectious diseases. Nat Protoc.Nature Research. 2021;16(11):5171-5192. doi:10.1038/s41596-021-00607-0 4)Stepniak M, Adam P, Massot C, et al. Study of the Implication of the Epithelium in the Development and Progression of Fibrosis in Ulcerative Colitis. In: Published by Oxford University Press on behalf of European Crohn’s and Colitis Organisation, ed. ECCO 2025. 2025:509-509 Conflict of interest: Mr. Stepniak, Marty: No conflict of interest Adam, Pierre: No conflict of interest Salée, Catherine: No conflict of interest Massot, Charlotte: No conflict of interest Vieujean, Sophie: No conflict of interest Reenaers, Catherine: No conflict of interest Loly, Jean-Philippe: No conflict of interest Coimbra, Carla: No conflict of interest Emmanuel, Decker: No conflict of interest Speca, Silvia: No conflict of interest Delvenne, Philippe: No conflict of interest Blétard, Noella: No conflict of interest Beq, Stéphanie: No conflict of interest Louis, Edouard: No conflict of interest Meuwis, Marie-Alice: No conflict of interest

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