A regulatory role for microRNA 33* in controlling lipid metabolism gene expression

Mol Cell Biol. 2013 Jun;33(11):2339-52. doi: 10.1128/MCB.01714-12. Epub 2013 Apr 1.

Abstract

hsa-miR-33a and hsa-miR-33b, intronic microRNAs (miRNAs) located within the sterol regulatory element-binding protein 2 and 1 genes (Srebp-2 and -1), respectively, have recently been shown to regulate lipid homeostasis in concert with their host genes. Although the functional role of miR-33a and -b has been highly investigated, the role of their passenger strands, miR-33a* and -b*, remains unclear. Here, we demonstrate that miR-33a* and -b* accumulate to steady-state levels in human, mouse, and nonhuman primate tissues and share a similar lipid metabolism target gene network as their sister strands. Analogous to miR-33, miR-33* represses key enzymes involved in cholesterol efflux (ABCA1 and NPC1), fatty acid metabolism (CROT and CPT1a), and insulin signaling (IRS2). Moreover, miR-33* also targets key transcriptional regulators of lipid metabolism, including SRC1, SRC3, NFYC, and RIP140. Importantly, inhibition of either miR-33 or miR-33* rescues target gene expression in cells overexpressing pre-miR-33. Consistent with this, overexpression of miR-33* reduces fatty acid oxidation in human hepatic cells. Altogether, these data support a regulatory role for the miRNA* species and suggest that miR-33 regulates lipid metabolism through both arms of the miR-33/miR-33* duplex.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3' Untranslated Regions
  • Animals
  • Base Sequence
  • Cell Line
  • Conserved Sequence
  • Fatty Acids / metabolism
  • Gene Expression Regulation*
  • Humans
  • Lipid Metabolism / genetics*
  • Liver / cytology
  • Liver / physiology
  • Macaca mulatta / genetics
  • Macrophages / cytology
  • Macrophages / physiology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • MicroRNAs / genetics*
  • MicroRNAs / metabolism

Substances

  • 3' Untranslated Regions
  • Fatty Acids
  • MIRN33a microRNA, human
  • MicroRNAs
  • Mirn33 microRNA, mouse