MiR-19a regulates PTEN expression to mediate glycogen synthesis in hepatocytes

Sci Rep. 2015 Jun 26:5:11602. doi: 10.1038/srep11602.

Abstract

MiR-19a, a member of mir-17-92 microRNA clusters, has been demonstrated to promote cell proliferation and angiogenesis via regulating the PI3K/AKT pathway, the major insulin signaling pathway. However, whether miR-19a plays an important role in glycogen synthesis in hepatocytes remains unknown. Here, we define the impact of miR-19a on glycogen synthesis and IL-6-induced reduced glycogenesis in hepatocytes and its underlying mechanisms. Our studies indicate that miR-19a was down-regulated in the livers of db/db mice and mice injected with IL-6, as well as mouse NCTC 1469 hepatocytes and HEP 1-6 hepatocytes treated by IL-6. We found that over-expression of miR-19a in NCTC 1469 cells and HEP 1-6 cells led to increased activation of the AKT/GSK pathway and synthesis of glycogen, whereas down-regulation of miR-19a impaired AKT/GSK phosphorylation and glycogenesis. Over-expression of miR-19a ameliorated IL-6-induced reduced glycogen synthesis in hepatocytes. Moreover, we identified PTEN as the target of miR-19a by a luciferase assay. Down-regulation of PTEN rescued the effects of miR-19a suppression on the activation of the AKT/GSK pathway and improved glycogenesis in NTC 1469 cells. These findings show for the first time that miR-19a might activate the AKT/GSK pathway and glycogenesis via down-regulation of PTEN expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Cell Line
  • Gene Expression Profiling / methods
  • Gene Expression Regulation*
  • Glycogen / biosynthesis*
  • Glycogen Synthase Kinases / metabolism
  • Hepatocytes / cytology
  • Hepatocytes / drug effects
  • Hepatocytes / metabolism*
  • Interleukin-6 / pharmacology
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • MicroRNAs / genetics*
  • Oligonucleotide Array Sequence Analysis
  • PTEN Phosphohydrolase / genetics*
  • PTEN Phosphohydrolase / metabolism
  • Phosphatidylinositol 3-Kinases / metabolism
  • Phosphorylation / genetics
  • Proto-Oncogene Proteins c-akt / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / genetics

Substances

  • Interleukin-6
  • MIRN19 microRNA, mouse
  • MicroRNAs
  • Glycogen
  • Phosphatidylinositol 3-Kinases
  • Glycogen Synthase Kinases
  • Proto-Oncogene Proteins c-akt
  • PTEN Phosphohydrolase
  • Pten protein, mouse