TWEAK/Fn14 Signaling Modulates Goblet Cell-Associated Mucin Responses in Mouse Small Intestinal Epithelial Organoids

Intestinal barrier dysfunction and mucus layer abnormalities are central features of inflammatory bowel disease, yet the epithelial mechanisms regulating goblet cell function remain incompletely understood. The TWEAK/Fn14 pathway is involved in intestinal inflammation, but its role in small intestinal epithelial responses, particularly in goblet cells, has not been fully clarified. In this study, we investigated TWEAK/Fn14 signaling using mouse small intestinal epithelial organoids. Fn14 was expressed in MUC2-positive cells in intestinal tissue, with staining preferentially observed toward the mucin-facing region. Fn14 staining was also observed in small intestinal epithelial organoids. TWEAK stimulation increased Tnf mRNA expression by approximately 1.56-fold and reduced Muc2 mRNA expression to approximately 66% of control, without markedly affecting epithelial proliferation or stem cell markers. TWEAK did not significantly alter the PAS-positive mucin area or AB-PAS-defined mucin composition, whereas PGM34 staining showed a non-significant tendency to increase. TNF treatment reproduced some of the TWEAK-associated changes, including reduced Muc2 mRNA expression and alterations in mucin-associated parameters, suggesting that TNF may contribute to some of the epithelial responses associated with TWEAK treatment. Treatment with an anti-TNF neutralizing antibody modified several TWEAK-associated responses, including changes in epithelial-associated gene expression and mucin-associated staining parameters. These findings suggest that TWEAK treatment is associated with goblet cell-related mucin responses in mouse small intestinal epithelial organoids, with possible involvement of TNF signaling.