Adiponectin increases fatty acid oxidation in skeletal muscle cells by sequential activation of AMP-activated protein kinase, p38 mitogen-activated protein kinase, and peroxisome proliferator-activated receptor alpha.
Adiponectin has recently received a great deal of attention due to its beneficial effects on insulin resistance and metabolic disorders. One of the mechanisms through which adiponectin exerts such effects involves an increase in fatty acid oxidation in muscle and liver. In the present study, we demonstrate that 5'-AMP-activated protein kinase (AMPK) and p38 mitogen-activated protein kinase (MAPK) are involved in the activation of peroxisome proliferator-activated receptor (PPAR)alpha by adiponectin in muscle cells. Adiponectin increases the transcriptional activity of PPARalpha and the expression of its target genes, including ACO, CPT1, and FABP3 in C2C12 myotubes. These effects were suppressed by the overexpression of a dominant-negative form of AMPK. Moreover, chemical inhibitors of AMPK and p38 MAPK potently repressed fatty acid oxidation and the induction of PPARalpha target gene expression by adiponectin. Interestingly, araA, an AMPK inhibitor, prevented the activation of p38 MAPK, whereas SB203580, a p38 MAPK inhibitor, did not affect AMPK activation, suggesting that p38 MAPK is a downstream signaling factor of AMPK. Taken together, these results suggest that adiponectin stimulates fatty acid oxidation in muscle cells by the sequential activation of AMPK, p38 MAPK, and PPARalpha.
Yoon
Myeong Jin
MJ
Department of Biological Sciences, Seoul National University, Gwanak-Gu, Seoul 151-742, Korea.
Lee
Gha Young
GY
Chung
Jun-Jae
JJ
Ahn
Young Ho
YH
Hong
Seung Hwan
SH
Kim
Jae Bum
JB
D055372:AMP-Activated Protein Kinases; D042962:Acyl-CoA Oxidase / Q000378:metabolism; D052242:Adiponectin / Q000502:physiology*; D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000378:metabolism; D002478:Cells, Cultured; D004789:Enzyme Activation; D005227:Fatty Acids / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009097:Multienzyme Complexes / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000166:cytology / Q000378:metabolism*; D010084:Oxidation-Reduction; D047493:PPAR alpha / Q000096:biosynthesis*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D015398:Signal Transduction; D014158:Transcription, Genetic / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
D052242:Adiponectin; D005227:Fatty Acids; D009097:Multienzyme Complexes; D047493:PPAR alpha; D042962:Acyl-CoA Oxidase; D002334:Carnitine O-Palmitoyltransferase; D017346:Protein Serine-Threonine Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D055372:AMP-Activated Protein Kinases