Premium
AMP‐activated protein kinase α1 silencing provides evidence for a Metformin‐induced decrease in FA uptake and oxidation and increase in glucose uptake and SIRT1 activity in L6 skeletal muscle cells
Author(s) -
Bogachus Lindsey D,
Turcotte Lorraine P
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1045.1
Subject(s) - ampk , amp activated protein kinase , chemistry , protein kinase a , gene silencing , endocrinology , medicine , glucose uptake , metformin , skeletal muscle , kinase , biochemistry , biology , insulin , gene
AMP‐activated protein kinase (AMPK) and SIRT1 have been shown to be key regulators of glucose and fatty acid (FA) metabolism. L6 skeletal muscle cells were treated using RNAi technology to genetically silence AMPKα1 (α1) and AMPKα2 (α2) and incubated ± AICAR ( A : 2mM, 2hr) or Metformin ( M : 2mM, 3hr). After treatment, glucose uptake (GU) and FA uptake (FAU) & oxidation (FAO) were measured using [2‐3H]deoxyglucose or [1‐14C]palmitate. AMPKα1 & AMPKα2 phosphorylation (~P), PGC‐1α acetylation (~A), and SIRT1 activity were measured. The effects of genetic and pharmacological treatments on metabolic parameters were assessed with ANOVA. AMPKα1 & AMPKα2 ~P measurements verified that the RNAi transfections were efficient ( P <0.05). Silencing of α1 eliminated the M‐induced decrease in FAU & FAO and blunted the M‐induced increase in GU ( P <0.05). Silencing of α2 eliminated the A‐induced increase in GU & FAO and reduced A‐induced FAU ( P <0.05). A & M treatments increased SIRT1 activity ( P <0.05). While silencing of α1 increased M‐induced SIRT1 activity, silencing of α2 increased both A‐ and M‐induced SIRT1 activity ( P <0.05). PGC‐1α ~A data confirmed the SIRT1 activity measurements. Our data show that in muscle cells the stimulatory effects of A on muscle metabolism occur via preferential ~P of AMPKα2 and that the inhibitory effects of M on FA metabolism occur via preferential ~P of AMPKα1. Funding: WiSE & IEB Research Award, USC