Glycogen Synthase Kinase 3 Is Essential for Intestinal Cell Niche and Digestive Function

WNT/β-catenin signaling is essential for intestinal stem cell development and self-renewal, while its dysregulation can drive tumorigenesis. GSK3, a key negative regulator of β-catenin, in intestinal homeostasis remains incompletely understood. In this study, we investigated the role of GSK3 in intestinal development, niche maintenance, and physiological function. Unlike Apc^Min/+ mice that developed intestinal polyps, neither GSK3α nor GSK3β deficiency disrupted intestinal homeostasis. However, complete GSK3 deletion (DKO) resulted in perinatal lethality, characterized by disturbed crypt-villus architecture, Paneth cell redistribution, and villus elongation. GSK3 deficiency disrupted the intestinal niche, leading to expanded and mislocalized stem cells and Paneth cells, along with reduced tuft and enteroendocrine cells. These alterations impaired nutrient absorption and gut motility. Mechanistically, β-catenin-positive cells were significantly increased following GSK3 deletion. Genetic ablation of β-catenin under GSK3-deficient conditions reduced stem and Paneth cell populations while restoring tuft and enteroendocrine cells, thereby ameliorating niche abnormalities and improving absorptive and peristaltic functions. This study indicates the essential role of GSK3/β-catenin signaling in maintaining intestinal niche integrity and digestive physiology, highlighting potential therapeutic targets for intestinal and digestive disorders.