Siphonaxanthin, a Carotenoid From Green Algae, Inhibits Lipogenesis in Hepatocytes via the Suppression of Liver X Receptor α Activity

Lipids. 2018 Jan;53(1):41-52. doi: 10.1002/lipd.12002. Epub 2018 Feb 15.

Abstract

Nonalcoholic fatty liver disease (NAFLD) has shown an increasing morbidity in recent years. Here, we demonstrated that siphonaxanthin (SPX), a rare marine carotenoid, exhibits a strong inhibitory effect on aggravated hepatic lipogenesis in vitro and would be a promising candidate in the prevention and alleviation of NAFLD in the future. In this study, we conducted a preliminary assessment of the effect of SPX on hepatic lipogenesis by using the HepG2 cell line, derived from human liver cancer, as a model of the liver. SPX significantly suppressed the excess accumulation of triacylglycerol induced by liver X receptor α (LXRα) agonist by downregulating a nuclear transcription factor named sterol regulatory element-binding protein-1c and a set of related genes. Moreover, fatty acid translocase (CD36) and fatty acid-binding protein-1, which regulates fatty acid uptake, also exhibited significant decrease in transcriptional levels. Furthermore, we found that SPX blocked LXRα activation and would be a promising candidate for antagonist of LXRα.

Keywords: Carotenoid; LXRα; SREBP-1c; hepatocyte; lipogenesis; siphonaxanthin.

MeSH terms

  • CD36 Antigens / genetics
  • Carotenoids / administration & dosage*
  • Carotenoids / chemistry
  • Chlorophyta / chemistry
  • Fatty Acids / metabolism
  • Hep G2 Cells
  • Hepatocytes / drug effects
  • Humans
  • Lipogenesis / drug effects
  • Liver X Receptors / antagonists & inhibitors
  • Liver X Receptors / genetics*
  • Non-alcoholic Fatty Liver Disease / drug therapy*
  • Non-alcoholic Fatty Liver Disease / genetics
  • Non-alcoholic Fatty Liver Disease / pathology
  • Sterol Regulatory Element Binding Protein 1 / genetics
  • Xanthophylls / administration & dosage*
  • Xanthophylls / chemistry

Substances

  • CD36 Antigens
  • Fatty Acids
  • Liver X Receptors
  • Sterol Regulatory Element Binding Protein 1
  • Xanthophylls
  • siphonaxanthin
  • Carotenoids