Phospho-BAD BH3 Mimicry Protects β Cells and Restores Functional β Cell Mass in Diabetes

Abstract

Strategies that simultaneously enhance the survival and glucose responsiveness of insulin-producing β cells will greatly augment β cell replacement therapies in type 1 diabetes (T1D). We show that genetic and pharmacologic mimetics of the phosphorylated BCL-2 homology 3 (BH3) domain of BAD impart β-cell-autonomous protective effects in the face of stress stimuli relevant to β cell demise in T1D. Importantly, these benefits translate into improved engraftment of donor islets in transplanted diabetic mice, increased β cell viability in islet grafts, restoration of insulin release, and diabetes reversal. Survival of β cells in this setting is not merely due to the inability of phospho-BAD to suppress prosurvival BCL-2 proteins but requires its activation of the glucose-metabolizing enzyme glucokinase. Thus, BAD phospho-BH3 mimetics may prove useful in the restoration of functional β cell mass in diabetes.