A-769662 activates AMPK beta1-containing complexes but induces glucose uptake through a PI3-kinase-dependent pathway in mouse skeletal muscle.
5'-AMP-activated protein kinase (AMPK) regulates several aspects of metabolism. Recently, A-769662 was shown to activate AMPK in skeletal muscle. However, no biological effects of AMPK activation by A-769662 in this tissue have been reported. We hypothesized that A-769662 would increase glucose uptake in skeletal muscle. We studied incubated soleus and extensor digitorum longus (EDL) muscles from 129S6/sv and C57BL/6 mice. Glucose uptake increased only in soleus from 129S6/sv when concentrations of A-769662 were 500 microM (approximately 15%, P < 0.05) and 1 mM (approximately 60%, P < 0.01). AMPK beta1- but not beta2-containing complexes were dose dependently activated by A-769662 in muscles from both genotypes (approximately 100% at 200 microM and 300-600% at 1 mM). The discrepancy between the A-769662-induced AMPK activation pattern and stimulation of glucose uptake suggested that these effects were unrelated. A-769662 increased phosphorylation of Akt in both muscles from both genotypes, with phosphorylation of T308 being significantly higher in soleus than in EDL in 129S6/sv mice (P < 0.01). In soleus from 129S6/sv mice, insulin receptor substrate 1-associated phosphatidylinositol 3 (PI3)-kinase activity was markedly increased with A-769662, and Akt phosphorylation and glucose uptake were inhibited by wortmannin while phosphorylation of acetyl-CoA carboxylase (S227) was unaffected. Thus, A-769662 activates beta1-containing AMPK complexes in skeletal muscle but induces glucose uptake through a PI3-kinase-dependent pathway. Although development of A-769662 has constituted a step forward in the search for AMPK activators targeting specific AMPK trimers, our data suggest that in intact muscle, A-769662 has off-target effects. This may limit use of A-769662 to study the role of AMPK in skeletal muscle metabolism.
Treebak
Jonas T
JT
Molecular Physiology Group, Copenhagen Muscle Research Centre, Department of Exercise and Sport Sciences, University of Copenhagen, Copenhagen, Denmark.
Birk
Jesper B
JB
Hansen
Bo F
BF
Olsen
Grith S
GS
Wojtaszewski
Jørgen F P
JF
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D000103:Acetyl-CoA Carboxylase / Q000378:metabolism; D000730:Androstadienes / Q000494:pharmacology; D000818:Animals; D001713:Biphenyl Compounds; D004789:Enzyme Activation; D005260:Female; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D051379:Mice; D018345:Mice, Knockout; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D055503:Protein Multimerization; D011753:Pyrones / Q000494:pharmacology*; D015398:Signal Transduction; D013876:Thiophenes / Q000494:pharmacology*; D000077191:Wortmannin
D055372:AMP-Activated Protein Kinases; D000103:Acetyl-CoA Carboxylase; D000730:Androstadienes; D001713:Biphenyl Compounds; D005947:Glucose; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011753:Pyrones; D013876:Thiophenes; D000077191:Wortmannin; C569522:Prkab2 protein, mouse; C512408:4-hydroxy-3-(4-(2-hydroxyphenyl)phenyl)-6-oxo-7H-thieno(2,3-b)pyridine-5-carbonitrile