Combinatorial transcription factor regulation of the cyclic AMP-response element on the Pgc-1α promoter in white 3T3-L1 and brown HIB-1B preadipocytes

Angeliki Karamitri, Andrew M Shore, Kevin Docherty, John R Speakman, Michael A Lomax

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

Cold stress in rodents increases the expression of UCP1 and PGC-1 alpha in brown and white adipose tissue. We have previously reported that C/EBP beta specifically binds to the CRE on the proximal Pgc-1 alpha promoter and increases forskolin-sensitive Pgc-1 alpha and Ucp1 expression in white 3T3-L1 preadipocytes. Here we show that in mice exposed to a cold environment for 24 h, Pgc-1 alpha, Ucp1, and C/ebp beta but not C/ebp alpha or C/ebp delta expression were increased in BAT. Conversely, expression of the C/EBP dominant negative Chop10 was increased in WAT but not BAT during cold exposure. Reacclimatization of cold-exposed mice to a warm environment for 24 h completely reversed these changes in gene expression. In HIB-1B, brown preadipocytes, forskolin increased expression of Pgc-1 alpha, Ucp1, and C/ebp beta early in differentiation and inhibited Chop10 expression. Employing chromatin immunoprecipitation, we demonstrate that C/EBP beta, CREB, ATF-2, and CHOP10 are bound to the Pgc-1 alpha proximal CRE, but CHOP10 does not bind in HIB-1B cell lysates. Forskolin stimulation and C/EBP beta overexpression in 3T3-L1 cells increased C/EBP beta and CREB but displaced ATF-2 and CHOP10 binding to the Pgc-1 alpha proximal CRE. Overexpression of ATF-2 and CHOP10 in 3T3-L1 cells decreased Pgc-1 alpha transcription. Knockdown of Chop10 in 3T3-L1 cells using siRNA increased Pgc-1 alpha transcription, whereas siRNA against C/ebp beta in HIB-1B cells decreased Pgc-1 alpha and Ucp1 expression. We conclude that the increased cAMP stimulation of Pgc-1 alpha expression is regulated by the combinatorial effect of transcription factors acting at the CRE on the proximal Pgc-1 alpha promoter.

Original languageEnglish
Pages (from-to)20738-20752
Number of pages15
JournalThe Journal of Biological Chemistry
Volume284
Issue number31
Early online date2 Jun 2009
DOIs
Publication statusPublished - 31 Jul 2009

Keywords

  • activating transcription factor 2
  • adipocytes
  • adipose tissue, brown
  • adipose tissue, white
  • aging
  • animals
  • CCAAT-enhancer-binding protein-beta
  • cold temperature
  • cyclic AMP
  • cyclic AMP response element-binding protein
  • down-regulation
  • gene knockdown techniques
  • humans
  • ion channels
  • mice
  • mitochondrial proteins
  • organ specificity
  • protein binding
  • protein isoforms
  • RNA, small interfering
  • rats
  • response elements
  • trans-activators
  • transcription factor CHOP
  • transcription, genetic

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