GSK-3β mediates dexamethasone-induced pancreatic β cell apoptosis

Aims: Glucocorticoids, such as dexamethasone, are widely used anti-inflammatory drugs. Their use is frequently associated with the development of steroid-associated diabetes. Pancreatic beta-cell dysfunction has been suggested to be one of the main causes of steroid-associated diabetes. However, the mechanism is not fully understood. Glycogen synthase kinase-3 beta (GSK-3 beta) is a multifunctional serine/threonine kinase and plays an important role in energy metabolism, cell growth and apoptosis. Therefore, the contribution of GSK-3 beta in dexamethasone-induced pancreatic beta-cell apoptosis was determined in the present study. Main methods: The effect of dexamethasone treatment on rat pancreatic beta-cell line (INS-1) apoptosis (determined by TUNEL and Flow Cytometry), generation of reactive oxidative stress (ROS), and the phosphorylation status of GSK-3 beta was determined. The inhibitory effect of GSK-3 beta inhibitor-lithium chloride (LiCl) on dexamethasone-induced beta-cell apoptosis was also evaluated. Key findings: Dexamethasone (0.1 mu M) treatment induced INS-1 apoptosis, which was associated with increased GSK-3 beta activation and increased NOX4-derived ROS generation. Pretreatment of INS-1 with LiCl inhibited dexamethasone induced ROS generation and INS-1 apoptosis. Significance: This study provides a new mechanism of Dex induced pancreatic beta cell apoptosis and may serve as a new therapeutic option for treating GC induced diabetes. (C) 2015 Elsevier Inc. All rights reserved.