Identification of HNF-4α as a key transcription factor to promote ChREBP expression in response to glucose

Sci Rep. 2016 Mar 31:6:23944. doi: 10.1038/srep23944.

Abstract

Transcription factor carbohydrate responsive element binding protein (ChREBP) promotes glycolysis and lipogenesis in metabolic tissues and cancer cells. ChREBP-α and ChREBP-β, two isoforms of ChREBP transcribed from different promoters, are both transcriptionally induced by glucose. However, the mechanism by which glucose increases ChREBP mRNA levels remains unclear. Here we report that hepatocyte nuclear factor 4 alpha (HNF-4α) is a key transcription factor for glucose-induced ChREBP-α and ChREBP-β expression. Ectopic HNF-4α expression increased ChREBP transcription while knockdown of HNF-4α greatly reduced ChREBP mRNA levels in liver cancer cells and mouse primary hepatocytes. HNF-4α not only directly bound to an E-box-containing region in intron 12 of the ChREBP gene, but also promoted ChREBP-β transcription by directly binding to two DR1 sites and one E-box-containing site of the ChREBP-β promoter. Moreover, HNF-4α interacted with ChREBP-α and synergistically promoted ChREBP-β transcription. Functionally, HNF-4α suppression reduced glucose-dependent ChREBP induction. Increased nuclear abundance of HNF-4α and its binding to cis-elements of ChREBP gene in response to glucose contributed to glucose-responsive ChREBP transcription. Taken together, our results not only revealed the novel mechanism by which HNF-4α promoted ChREBP transcription in response to glucose, but also demonstrated that ChREBP-α and HNF-4α synergistically increased ChREBP-β transcription.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / genetics*
  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / metabolism
  • Genes, Reporter
  • Glucose / metabolism
  • Glucose / pharmacology*
  • HEK293 Cells
  • Hep G2 Cells
  • Hepatocyte Nuclear Factor 4 / genetics*
  • Hepatocyte Nuclear Factor 4 / metabolism
  • Hepatocytes / cytology
  • Hepatocytes / drug effects*
  • Hepatocytes / metabolism
  • Humans
  • Liver / cytology
  • Liver / drug effects*
  • Liver / metabolism
  • Luciferases / genetics
  • Luciferases / metabolism
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Nucleotide Motifs
  • Primary Cell Culture
  • Promoter Regions, Genetic
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction
  • Transcriptional Activation / drug effects*

Substances

  • Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
  • HNF4A protein, human
  • Hepatocyte Nuclear Factor 4
  • MLXIPL protein, human
  • Protein Isoforms
  • RNA, Messenger
  • Luciferases
  • Glucose