Ileal Crohn’s disease exhibits reduced activity of phospholipase C-β3 (PLC-β3)-dependent Wnt/b-catenin signaling pathway [microarray]

Crohn’s disease is a chronic, debilitating inflammatory bowel disease. Here we report a critical role for phospholipase C-β3 (PLC-β3) in intestinal homeostasis. In PLC-β3- deficient mice, exposure to oral dextran sodium sulfate induced lethality and severe inflammation in the small intestine. The lethality was due to PLC-β3 deficiency in multiple non-hematopoietic cell types. PLC-β3 deficiency resulted in reduced Wnt/β-catenin signaling, which is essential for homeostasis and regeneration of the intestinal epithelium. PLC-β3 regulated the Wnt/β-catenin pathway in small intestinal epithelial cells (IECs) at transcriptional, epigenetic, and potentially protein-protein interaction levels. PLC-β3- deficient IECs were unable to respond to stimulation by R-spondin 1, an enhancer of Wnt/β-catenin signaling. Reduced expression of PLC-β3 and its signature genes was found in biopsies of ileal Crohn’s disease patients. PLC-β regulation of Wnt signaling was evolutionally conserved in Drosophila. Our data indicate that reduction of PLC-β3- mediated Wnt/β-catenin signaling contributes to the pathogenesis of ileal Crohn’s disease. To gain insight into the molecular mechanisms by which Plcb3 deficiency increases DSS susceptibility, gene expression in isolated small intestinal IECs, whole jejunum or whole ileum from WT, Plcb3_KO, Plcb3_Flox or Plcb3_deltaIEC mice with or without 3% DSS treatment was analyzed using DNA microarray.