Regulation of Glucose Uptake and Inflammation by FOXO1 and FOXO3 in Skeletal Muscle

Forkhead box class O (FoxO) transcription factors regulate whole body energy metabolism, skeletal muscle mass and substrate switching. To elucidate the role of FOXO in skeletal muscle, dominant negative (dn) constructs for FOXO1 (FOXO1dn) or FOXO3 (FOXO3dn) were transfected by electroporation into mouse tibialis anterior muscle and glucose uptake, signal transduction, and glucose stimulated gene expression profiles were assessed. Results were compared against contralateral control transfected muscle. Transcriptomic analysis revealed major pathways affected by FOXO1dn or FOXO3dn revolve around metabolism and inflammation. 6 mice for FOXO1dn or FOXO3dn were electroporated in tibialis anterior with either construct or empty vector in contralateral leg. One week post-electroporation, mice were fasted for 4 h, and glucose uptake was measured in vivo using a modified oral glucose tolerance test. Mice were anesthetized with an intraperitoneal injection of Avertin, and electroporated tibialis anterior muscle was removed and snap-frozen. RNA was extracted from electroporated muscle utilizing the EZ RNA extraction kit, and hybridized to an Affymetrix Mouse Gene 2.1 ST array