P074 Interferon-γ promotes antigen processing and presentation pathway in the intestinal epithelium of patients with Crohn’s disease
Hong, S.N.(1)*;Lee, C.(1);Kim, J.E.(1);Kim, E.R.(1);Chang, D.K.(1);Kim, Y.H.(1);
(1)Samsung Medical Center- Sungkyunkwan University School of Medicine, Department of Medicine, Seoul, Korea- Republic Of;
Background
Interferon-γ (IFN-γ) is a major driver of excessive immune response, leading to intestinal mucosal damage and contributing the pathogenesis of Crohn’s diseases (CD). In contrast to the inflammatory cells and immune system, IFN-γ-induced cellular responses has not been well documented in the intestinal epithelium. The intestinal epithelium consists of multiple cell types and patient-derived intestinal organoid model may be appropriate to evaluate the IFN-γ-induced epithelial cellular responses in patients with CD.
Methods
To evaluate the IFN-γ-mediated epithelial cellular responses, human small intestinal organoids (enteroids) derived from the controls (n=6) and patients with Crohn’s disease (CD, n=10) were constructed. We focused on the IFN-γ-induced cell death mechanism upregulated in CD enteroids and validated them in surgically resected small intestine in patients with active CD.
Results
As the concentration of IFN-γ increased in the culture medium, the organoid-forming efficiency decreased steadily, which did not differ between control and CD enteroids. The enteroid viability measured using MTT was estimated to be 83.10 pg/ml for EC50. In control and CD enteroids treated with 100 pg/ml IFN-γ, PANoptosis was the main inflammatory cell death mechanism. Bulk and single-cell RNA sequencing revealed that IFN-γ induced the expression of MHC class II-associated genes, co-inhibitory molecule CD274 (PD-L1), and IDO1 in control and CD enteroids, which may be associated with peripheral tolerance in the absence of exogenous antigens. Gene set enrichment analysis identified an up-regulated antigen processing and presentation pathway with increased expression of MHC class I molecules in IFN-γ-treated CD enteroids compared to IFN-γ-treated control enteroids (normalized enrichment score=2.13, p=0.002, q=0.005). IFN-γ-induced MHC class I pathway could result in T cell-mediated cytotoxicity in CD enteroids. The selective JAK1 inhibitor, upadacitinib, inhibited the IFN-γ-induced PANoptosis and T cell-mediated cytotoxicity in CD enteroids. The expression of HLA-A and B was higher in the inflamed small intestine in patients with CD than those in patients with ischemic enteritis.
Conclusion
IFN-γ promotes antigen processing and presentation pathway in the intestinal epithelium. In patients with CD, increased expression of MHC class I molecules may induce T cell-mediated cytotoxicity, which could contribute to the development of CD.