AMPD1: A novel therapeutic target for reversing insulin resistance

Abstract

Background: Insulin resistance is one of the hallmark manifestations of obesity and Type II diabetes and reversal ofthis pathogenic abnormality is an attractive target for new therapies for Type II diabetes. A recent report that metformin,a drug known to reverse insulin resistance, demonstrated in vitro the metformin can inhibit AMP deaminase (AMPD)activity. Skeletal muscle is one of the primary organs contributing to insulin resistance and that the AMPD1 gene isselectively expressed at high levels in skeletal muscle.Methods: Recognizing the background above, we asked if genetic disruption of the AMPD1 gene might ameliorate themanifestations of insulin resistance. AMPD1 deficient homozygous mice and control mice fed normal chow diet or ahigh-fat diet, and blood analysis, glucose tolerance test and insulin tolerance test were performed. Also, skeletal musclemetabolism and gene expression including nucleotide levels and activation of AMP activated protein kinase (AMP kinase)were evaluated in both conditions. Results: Disruption of the AMPD1 gene leads to a less severe state of insulin resistance, improved glucose tolerance andenhanced insulin clearance in mice fed a high fat diet. Given the central role of AMP kinase in insulin action, and itsresponse to changes in AMP concentrations in the cell, we examined the skeletal muscle of the AMPD1 deficient miceand found that they have greater AMP kinase activity as evidenced by higher levels of phosphorylated AMP kinase.Conclusions: Taken together these data suggest that AMPD may be a new drug target for the reversal of insulinresistance and the treatment of Type II diabetes.