Single-agent FOXO1 inhibition normalizes glycemia and induces gut β-like cells in streptozotocin-diabetic mice

OBJECTIVES: Insulin treatment remains the sole effective intervention for Type 1 Diabetes. Here, we investigated the therapeutic potential of converting intestinal epithelial cells to insulin-producing, glucose-responsive β-like cells by targeted inhibition of FOXO1. We have previously shown that this can be achieved by genetic ablation in gut Neurogenin3 progenitors, adenoviral or shRNA-mediated inhibition in human gut organoids, and chemical inhibition in Akita mice, a model of insulin-deficient diabetes. METHODS: We profiled two novel FOXO1 inhibitors in reporter gene assays, and hepatocyte gene expression studies, and in vivo pyruvate tolerance test (PTT) for their activity and specificity. We evaluated their glucose-lowering effect in mice rendered insulin-deficient by administration of streptozotocin. RESULTS: We provide evidence that two novel FOXO1 inhibitors, FBT432 and FBT374 have glucose-lowering and gut β-like cell-inducing properties in mice. FBT432 is also highly effective in combination with a Notch inhibitor in this model. CONCLUSION: The data add to a growing body of evidence suggesting that FOXO1 inhibition be pursued as an alternative treatment to insulin administration in diabetes.