Abstract
Glucose incorporation is regulated mainly by GLUT4 in skeletal muscles. Here we report that treatment of L6 myotubes with scriptide, a hydroxamic acid-based histone deacetylase (HDAC) inhibitor, stimulated 2-deoxyglucose uptake. The effect appeared only after 24 hr, resulting in 2.4-fold glucose uptake at treatment day 6. Scriptide acted synergistically with insulin, indicating it stimulated a distinct pathway from the insulin signaling pathway. It was not observed in undifferentiated myoblasts or 3T3-L1 adipocytes, suggesting a muscle-specific effect of scriptide. A five-carbon chain and hydroxamic acid, essential for histone deacetylase inhibition, were indispensable for this effect, and trichostatin A stimulated glucose uptake as well. Scriptide increased the cellular content of GLUT4, and induced GLUT4 translocation, but GLUT4 mRNA level did not change, indicating scriptide functions posttranslationally. Our results indicated a novel function for HDAC inhibitors of increasing GLUT4 content and its translocation in muscle cells, resulting in stimulation of glucose uptake.
