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AMPK activation increases fatty acid oxidation in skeletal muscle by activating PPARalpha and PGC-1

Woo Je Lee1, Mina Kim, Hye-Sun Park

  • 1Department of Internal Medicine, University of Ulsan College of Medicine, Seoul, Republic of Korea.

Biochemical and Biophysical Research Communications
|December 21, 2005
PubMed

Insights

AMP-activated protein kinase (AMPK) activation stimulates long-term fatty acid oxidation in skeletal muscle. This involves a new pathway mediated by PPARalpha and PGC-1, enhancing gene expression for sustained metabolic effects.

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Exercise Physiology

Background:

  • AMP-activated protein kinase (AMPK) activation is known to increase fatty acid oxidation in skeletal muscle.
  • The short-term mechanism involves reduced malonyl CoA concentrations.
  • Long-term effects of AMPK activation on fatty acid metabolism require further elucidation.

Purpose of the Study:

  • To investigate the molecular mechanisms underlying the long-term stimulation of fatty acid oxidation by AMPK activation in skeletal muscle.
  • To identify key transcriptional regulators involved in this process.

Main Methods:

  • Utilized cultured muscle cells and mouse skeletal muscle models.
  • Administered 5-aminoimidazole-4-carboxamide ribonucleoside (AICAR) to activate AMPK.
  • Employed small interfering RNAs (siRNAs) to inhibit peroxisome proliferator-activated receptor alpha (PPARalpha) and peroxisome proliferator-activated receptor gamma coactivator 1 (PGC-1).
  • Measured mRNA expression of PPARalpha target genes and PGC-1.

Main Results:

  • AICAR-induced AMPK activation increased mRNA expression of PPARalpha target genes and PGC-1 in muscle cells and mouse skeletal muscle.
  • Inhibition of PPARalpha and PGC-1 using siRNAs abolished the AICAR-stimulated increase in fatty acid oxidation.
  • These findings indicate a crucial role for PPARalpha and PGC-1 in mediating the long-term effects of AICAR on fatty acid metabolism.

Conclusions:

  • A novel transcriptional regulatory mechanism involving PPARalpha and PGC-1 mediates the long-term stimulation of fatty acid oxidation in skeletal muscle by AICAR.
  • This pathway provides new insights into the metabolic adaptations to AMPK activation in muscle tissue.
  • Highlights potential therapeutic targets for metabolic disorders through modulation of this pathway.

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