A Novel Role for RARα Agonists as Apolipoprotein CIII Inhibitors Identified from High Throughput Screening

Sci Rep. 2017 Jul 19;7(1):5824. doi: 10.1038/s41598-017-05163-w.

Abstract

Elevated triglyceride (TG) levels are well-correlated with the risk for cardiovascular disease (CVD). Apolipoprotein CIII (ApoC-III) is a key regulator of plasma TG levels through regulation of lipolysis and lipid synthesis. To identify novel regulators of TG levels, we carried out a high throughput screen (HTS) using an ApoC-III homogenous time resolved fluorescence (HTRF) assay. We identified several retinoic acid receptor (RAR) agonists that reduced secreted ApoC-III levels in human hepatic cell lines. The RARα specific agonist AM580 inhibited secreted ApoC-III by >80% in Hep3B cells with an EC50 ~2.9 nM. In high-fat diet induced fatty-liver mice, AM580 reduced ApoC-III levels in liver as well as in plasma (~60%). In addition, AM580 treatment effectively reduced body weight, hepatic and plasma TG, and total cholesterol (TC) levels. Mechanistically, AM580 suppresses ApoC-III synthesis by downregulation of HNF4α and upregulation of SHP1 expression. Collectively, these studies suggest that an RARα specific agonist may afford a new strategy for lipid-lowering and CVD risk reduction.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apolipoprotein C-III / antagonists & inhibitors*
  • Apolipoprotein C-III / blood
  • Apolipoprotein C-III / genetics
  • Cell Line, Tumor
  • Diet, High-Fat
  • Gene Expression Regulation / drug effects
  • Hepatocyte Nuclear Factor 4 / metabolism
  • High-Throughput Screening Assays*
  • Humans
  • Liver / metabolism
  • Mice
  • Retinoic Acid Receptor alpha / agonists*
  • Triglycerides / blood

Substances

  • Apolipoprotein C-III
  • Hepatocyte Nuclear Factor 4
  • Hnf4a protein, mouse
  • Retinoic Acid Receptor alpha
  • Triglycerides