Compound K, intestinal metabolite of ginsenoside, attenuates hepatic lipid accumulation via AMPK activation in human hepatoma cells.
Compound K (CK) is a major intestinal metabolite of ginsenosides derived from ginseng radix. Although antidiabetic and antihyperlipidemic activities of CK have been investigated in recent years, action mechanism of CK remains poorly understood. Therefore, we examined whether CK affects the lipid metabolism in insulin-resistant HepG2 human hepatoma cells. In this study, a significant increase in AMP-activated protein kinase (AMPK) was observed when the cells were treated with CK. Activation of AMPK was also demonstrated by measuring the phosphorylation of acetyl-CoA carboxylase (ACC), a substrate of AMPK. CK attenuated gene expression of sterol regulatory element-binding protein 1c (SREBP1c) in time- and dose-dependent manners. Genes for fatty acid synthase (FAS) and stearoyl-CoA desaturase 1 (SCD1), well-known target molecules of SREBP1c, were also suppressed. In contrast, gene expressions of peroxisome proliferator-activated receptor alpha (PPAR-alpha) and CD36 were increased. These effects were reversed by treatment of compound C, an AMPK inhibitor. However, there were no differences in gene expressions of SREBP2, hydroxymethyl glutaryl CoA reductase (HMGR), and low-density-lipoprotein receptor (LDLR). Taken together, AMPK mediates CK induced suppression and activation of SREBP1c and PPAR-alpha, respectively, and these effects seem to be one of antidiabetic and/or antihyperlipidemic mechanisms of CK in insulin-resistant HepG2 human hepatoma cells.
Kim
Do Yeon
DY
Pharmacology and Clinical Pharmacy Laboratory, College of Pharmacy, Kyung Hee University, 1 Hoegi-dong, Dongdaemun-gu, Seoul 130-701, Korea.
Yuan
Hai Dan
HD
Chung
In Kyung
IK
Chung
Sung Hyun
SH
D055372:AMP-Activated Protein Kinases / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular; D045744:Cell Line, Tumor; D004789:Enzyme Activation / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects; D036145:Ginsenosides / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D050356:Lipid Metabolism / Q000187:drug effects* / Q000235:genetics; D008099:Liver / Q000201:enzymology*; D008113:Liver Neoplasms
D055372:AMP-Activated Protein Kinases; D036145:Ginsenosides; C112772:ginsenoside compound K