The AMPK-SIRT signaling network regulates glucose tolerance under calorie restriction conditions

• DOI: 10.1016/j.lfs.2014.01.080
• Publication Date: 2014-02-12T23:16:06Z
• Authors: M.F.P. Silvestre; B. Viollet; P.W. Caton; J. Leclerc; I. Sakakibara; M. Foretz; M.C. Holness; M.C. Sugden
• Keywords: Calorie Restriction; Calorie

SIRT1 and AMP-activated protein kinase (AMPK) share common activators, actions and target molecules. Previous studies have suggested that a putative SIRT1-AMPK regulatory network could act as the prime initial sensor for calorie restriction-induced adaptations in skeletal muscle-the major site of insulin-stimulated glucose disposal. Our study aimed to investigate whether a feedback loop exists between AMPK and SIRT1 in skeletal muscle and how this may be involved glucose tolerance.To investigate this, we used skeletal muscle-specific AMPKα1/2 knockout mice (AMPKα1/2(-/-)) fed ad libitum (AL) or a 30% calorie restricted (CR) diet and L6 rat myoblasts incubated with SIRT1 inhibitor (EX527).CR-AMPKα1/2(-/-) displayed impaired glucose tolerance (*p<0.05), in association with down-regulated SIRT1 and PGC-1α expression (<300% vs. CR-WT, (±±)p<0.01). Moreover, AMPK activity was decreased following SIRT1 inhibition in L6 cells (~0.5-fold vs. control, *p<0.05).This study demonstrates that skeletal muscle-specific AMPK deficiency impairs the beneficial effects of CR on glucose tolerance and that these effects may be dependent on reduced SIRT1 levels.