Lack of β-catenin in early life induces abnormal glucose homeostasis in mice

Wingless and iNT-1 (WNT) pathway members are critical for pancreatic development and exocrine tissue formation. Recently, much attention has focused on delineating the roles of beta-catenin in pancreatic organogenesis. However, little is known about the involvement of beta-catenin in the endocrine or exocrine function of the mature pancreas. We report for the first time the impact of beta-catenin deletion in the pancreatic beta cells. We targeted the deletion of the beta-catenin gene in pancreatic beta cells by crossing a floxed beta-catenin mouse strain with a RIP-Cre mouse strain. Surprisingly, the majority of the mutant mice died shortly after birth and had deregulated glucose and insulin levels. The newborn mutant pancreases demonstrated increased insulin content, reflecting a defect in insulin release confirmed in vitro. Moreover, there was a reduction in total endocrine tissue at birth, while cellularity in islets was greater, suggesting that lack of beta-catenin affects beta cell size. Some newborns survived beta-catenin deletion and showed a milder phenotype during adulthood. The deletion of beta-catenin in the maturing beta cells negatively impacts on islet morphology and function. This work reveals that lack of beta-catenin in early life is related to severe deregulation of glucose homeostasis.