Inhibiting the response to VEGF in diabetes.

Inhibition of the vascular endothelial growth factor (VEGF)-VEGF receptor 2 (VEGFR2) signaling axis may play a role in endothelial dysfunction and serious vascular complications associated with diabetes. In this issue, Warren et al. identified a ligand-independent, receptor tyrosine kinase-independent VEGFR2 signaling pathway that is responsible for impaired responses to VEGF in diabetic endothelial cells. Reactive oxygen species (ROS) resulting from the hyperglycemic status promoted activation and subsequent degradation of VEGFR2 in a ligand-independent manner. Consequently, VEGF-VEGFR2 signaling was inhibited due to depletion of VEGFR2 at the cell surface. Activation of this ligand-independent, ROS-induced VEGFR2 signaling was mediated by the Src family of kinases and occurred in the Golgi compartment in the endothelial cells. Blocking ROS production by antioxidants effectively reversed VEGFR2 deficiency at the cell surface in hyperglycemia. These findings suggest that ROS-induced VEGFR2 signaling might be a promising new target for the treatment of vascular diseases in diabetes.