AMPK and SREBP-1c mediate the anti-adipogenic effect of β-hydroxyisovalerylshikonin

Int J Mol Med. 2016 Mar;37(3):816-24. doi: 10.3892/ijmm.2016.2484. Epub 2016 Feb 8.

Abstract

β-hydroxyisovalerylshikonin (β-HIVS), which is a natural naphthoquinone compound, is one of the main chemicals isolated from a therapeutic plant, Lithospermum erythrorhizon. In the present study, we demonstrated that β-HIVS inhibited the adipogenesis of 3T3-L1 cells through AMP-activated protein kinase (AMPK)-mediated modulation of sterol regulatory element binding protein (SREBP)‑1c. The anti-adipogenic effect of β-HIVS was accompanied by the increased phosphorylation of AMPK and precursor SREBP‑1c. In β-HIVS-treated 3T3-L1 cells, AMPK was activated and phosphorylated precursor SREBP‑1c, preventing the cleavage of precursor SREBP‑1c to mature SREBP‑1c. Expression of the fat-forming enzymes, acetyl-CoA carboxylase (ACC)1, fatty acid synthase (FAS) and stearoyl-CoA desaturase (SCD)1, which are transcribed by mature SREBP‑1c, were downregulated, resulting in reduced intracellular fat accumulation. The anti-adipogenic effect of β-HIVS was significantly attenuated by AMPK knockdown. Knockdown of AMPK using siRNA decreased the phosphorylation of precursor SREBP‑1c and increased the levels of mature SREBP. The levels of the fat-forming enzymes, ACC1, FAS and SCD1, as well as intracellular fat accumulation were also significantly increased by AMPK knockdown. These results suggest that β-HIVS activated AMPK, which was followed by the downregulation of mature SREBP‑1c and fat-forming enzymes, leading to the inhibition of adipogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • AMP-Activated Protein Kinases / genetics
  • AMP-Activated Protein Kinases / metabolism*
  • Acetyl-CoA Carboxylase / metabolism
  • Aldehyde Oxidoreductases / metabolism
  • Animals
  • Cell Survival / drug effects
  • Cell Survival / genetics
  • Mice
  • Naphthoquinones / pharmacology
  • Naphthoquinones / poisoning*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Stearoyl-CoA Desaturase / metabolism
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Sterol Regulatory Element Binding Protein 1 / metabolism*

Substances

  • Naphthoquinones
  • Sterol Regulatory Element Binding Protein 1
  • beta-hydroxyisovalerylshikonin
  • shikonin
  • Stearoyl-CoA Desaturase
  • Aldehyde Oxidoreductases
  • fatty acid reductase
  • AMP-Activated Protein Kinases
  • Acetyl-CoA Carboxylase