Abstract
Microvillus inclusion disease (MVID) is a congenital diarrheal disorder, caused by inactivating mutations in myosin Vb (MYO5B). MYO5B-deficient mice and cell lines have demonstrated the importance of MYO5B in brush border development; however, the previous models lacked specificity to test intestinal stem cell functions. In the present study, we investigated the effects of progressive MYO5B deficiency originating in intestinal crypt cells utilizing mouse models. Our transcriptomic and multiplex immunostaining datasets demonstrate that MYO5B is critical for intestinal stem cell function. MYO5B-deficient crypts acquire a hyperproliferative phenotype with incomplete cell differentiation in vivo and an elevated organoid formation rate compared to control crypts. An evident disruption in mitochondrial structure and fatty acid metabolism likely underlies these crypt phenotypes. Consistent with mouse models, MVID patient biopsies demonstrate abnormal expansion of the proliferative zone along with villus blunting. These data reveal the direct role of MYO5B in intestinal epithelial progenitor cell functions.