Compartment-specific roles for WNT2B in human intestinal development and function

Wnt Family Member 2B (WNT2B) mutations result in Diarrhea-9, a congenital diarrhea syndrome with an extreme phenotype and unique histological defects. Attempts to model Diarrhea-9 in rodents and study patient epithelial tissue have not been able to fully reproduce the human phenotype, making understanding this condition challenging. Here, we aimed to interrogate the mechanisms and the specific cellular compartment contributing to Diarrhea-9 using a human intestinal organoid model. Live and histological imaging revealed partial epithelial delamination in human intestinal organoids with WNT2B loss, which was absent in controls. A significant number of crypts in human intestinal organoids with WNT2B loss lacked olfactomedin 4 (OLFM4), a surrogate marker of stem cell activity. Key transcriptomic pathways altered between groups included trafficking of apical digestion proteins, which was confirmed via immunofluorescence. Patient-derived enteroid proteomic analysis revealed similar results. Recombination experiments in human intestinal organoids suggested compartment-specific effects of WNT2B loss, with WNT2B-deficient mesenchyme producing a more pronounced disruption of epithelial architecture and organization. These findings suggest compartment-specific roles for WNT2B in human intestinal development and function, with WNT2B-deficient mesenchyme having a particularly strong influence on epithelial architecture and organization. This study further highlights human intestinal organoids as a useful model for investigating human-specific intestinal disorders that are not fully recapitulated in murine models.