Production of reactive oxygen species (ROS) is a key instigator of b-cell dysfunction in diabetes. The pleiotropic cytokine interleukin 6 (IL-6) has previously been linked to b-cell autophagy but has not been studied in the context of b-cell antioxidant response. We used a combination of animal models of diabetes and analysis of cultured human islets and rodent b-cells to study how IL-6 influences antioxidant response. We show that IL-6 couples autophagy to antioxidant response and thereby reduces ROS in b-cells and human islets. b-Cell-specific loss of IL-6 signaling in vivo renders mice more susceptible to oxidative damage and cell death through the selective b-cell toxins streptozotocin and alloxan. IL-6-driven ROS reduction is associated with an increase in the master antioxidant factor NRF2, which rapidly translocates to the mitochondria to decrease mitochondrial activity and stimulate mitophagy. IL-6 also initiates a robust transient decrease in cellular cAMP levels, likely contributing to the stimulation of mitophagy to mitigate ROS. Our findings suggest that coupling autophagy to antioxidant response in b-cells leads to stress adaptation that can reduce cellular apoptosis. These findings have implications for b-cell survival under diabetogenic conditions and present novel targets for therapeutic intervention.
ASJC Scopus subject areas
- Internal Medicine
- Endocrinology, Diabetes and Metabolism