RESUMEN
High-fat diet (HFD)-fed mouse models have been widely used to study early type 2 diabetes. Decreased ß-cell glucokinase (GCK) expression has been observed in HFD-induced diabetes. However, owing to its crucial roles in glucose metabolism in the liver and in islet ß-cells, the contribution of decreased GCK expression to the development of HFD-induced diabetes is unclear. Here, we employed a ß-cell-targeted gene transfer vector and determined the impact of ß-cell-specific increase in GCK expression on ß-cell function and glucose handling in vitro and in vivo Overexpression of GCK enhanced glycolytic flux, ATP-sensitive potassium channel activation and membrane depolarization, and increased proliferation in Min6 cells. ß-cell-targeted GCK transduction did not change glucose handling in chow-fed C57BL/6 mice. Although adult mice fed a HFD showed reduced islet GCK expression, impaired glucose tolerance and decreased glucose-stimulated insulin secretion (GSIS), ß-cell-targeted GCK transduction improved glucose tolerance and restored GSIS. Islet perifusion experiments verified restored GSIS in isolated HFD islets by GCK transduction. Thus, our data identify impaired ß-cell GCK expression as an underlying mechanism for dysregulated ß-cell function and glycemic control in HFD-induced diabetes. Our data also imply an etiological role of GCK in diet-induced diabetes.This article has an associated First Person interview with the first author of the paper.