Background/Purpose: Axial Spondyloarthritis (AxSpA) is a chronic inflammatory disease affecting both the joints and gut, with 60% of patients showing microscopic and 10% overt IBD symptoms. The macrophage migration inhibitory factor (MIF) has emerged as a key factor in AxSpA’s complex etiology, noted in SKG mice studies where MIF’s modulation altered disease outcomes. However, MIF’s exact role in AxSpA-induced gut inflammation remains underexplored.

Methods: Small intestinal crypts were isolated from both SKG and MIFKO-SKG mice. The crypts were then embedded in an extracellular matrix (Matrigel) and cultured in a medium supplemented with growth factors essential for stem cell maintenance and organoid growth. The organoids were observed for a period to assess their formation, structural development and differential gene expression. Differentiation was characterized by IHC staining for markers of key intestinal cell types, including enterocytes, goblet cells, Paneth cells, enteroendocrine cells and assessing gene expression through qPCR.

Results: The study demonstrated successful culturing of small intestinal organoids from both SKG and MIFKO-SKG mice, with observable differences in organoid formation rates, sizes, and morphologies. SKG-derived organoids showed a consistent growth pattern, whereas MIFKO-SKG-derived organoids exhibited variations in proliferation rates and differentiation efficiency. Notably, the genetic modifications in MIFKO-SKG mice appeared to influence the gene expression in the organoids, showing downregulation in stem cell markers (LGR5, OLFM4), tight junction markers (OCLN, CLDND1), and Paneth cell markers (LYZ1 and MMP7), along with upregulation in the Goblet cell marker (MUC2). This had a marked impact on the morphology and development rate of the structures. Furthermore, the downregulation of tight junction markers led to increased leakiness and intestinal permeability, as evidenced by the FITC-dextran experiment.

Conclusion: Our findings indicate that the genetic background of mouse models significantly affects the in vitro behavior of small intestinal organoids, including their growth kinetics and cellular differentiation patterns. The observed differences between SKG and MIFKO-SKG derived organoids underscore the importance of genetic factors in intestinal biology of AxSpA. This study highlights the value of intestinal organoids as a model system for dissecting the genetic contributions of AxSpA model to intestinal pathologies, potentially paving the way for novel therapeutic strategies targeting autoimmune and other gastrointestinal diseases.

ACR Meeting Abstracts - https://acrabstracts.org/abstract/culturing-and-comparative-analysis-of-small-intestinal-organoids-from-skg-and-mifko-skg-mice/