Myristic Acid Enhances Diacylglycerol Kinase delta-Dependent Glucose Uptake in Myotubes

摘要

Decreased expression of diacylglycerol kinase (DGK) delta in skeletal muscles attenuates glucose uptake and is closely related to the pathogenesis of type 2 diabetes. Therefore, up-regulation of DGK delta expression is thought to protect and improve glucose homoeostasis in type 2 diabetes. We recently determined that myristic acid (14:0), but not palmitic (16:0) or stearic (18:0) acid, significantly increased DGK delta 2 protein expression in mouse C2C12 myotubes. In the current study, we analyzed whether myristic acid indeed enhances glucose uptake in C2C12 myotubes. We observed that myristic acid caused similar to 1.4-fold increase in insulin-independent glucose uptake. However, palmitic and stearic acids failed to enhance glucose uptake. DGK delta-specific siRNA decreased myristic acid-dependent increase of glucose uptake. Moreover, overexpression of DGK delta 2 enhanced glucose uptake in C2C12 cells in the absence of myristic acid treatment. Taken together, these results strongly suggest that myristic acid enhances basal glucose uptake in myotubes in a DGK delta 2 expression-dependent manner.