Transcriptional profiling reveals divergent roles of PPARalpha and PPARbeta/delta in regulation of gene expression in mouse liver

Physiol Genomics. 2010 Mar 3;41(1):42-52. doi: 10.1152/physiolgenomics.00127.2009. Epub 2009 Dec 15.

Abstract

Little is known about the role of the transcription factor peroxisome proliferator-activated receptor (PPAR) beta/delta in liver. Here we set out to better elucidate the function of PPARbeta/delta in liver by comparing the effect of PPARalpha and PPARbeta/delta deletion using whole genome transcriptional profiling and analysis of plasma and liver metabolites. In fed state, the number of genes altered by PPARalpha and PPARbeta/delta deletion was similar, whereas in fasted state the effect of PPARalpha deletion was much more pronounced, consistent with the pattern of gene expression of PPARalpha and PPARbeta/delta. Minor overlap was found between PPARalpha- and PPARbeta/delta-dependent gene regulation in liver. Pathways upregulated by PPARbeta/delta deletion were connected to innate immunity and inflammation. Pathways downregulated by PPARbeta/delta deletion included lipoprotein metabolism and various pathways related to glucose utilization, which correlated with elevated plasma glucose and triglycerides and reduced plasma cholesterol in PPARbeta/delta-/- mice. Downregulated genes that may underlie these metabolic alterations included Pklr, Fbp1, Apoa4, Vldlr, Lipg, and Pcsk9, which may represent novel PPARbeta/delta target genes. In contrast to PPARalpha-/- mice, no changes in plasma free fatty acid, plasma beta-hydroxybutyrate, liver triglycerides, and liver glycogen were observed in PPARbeta/delta-/- mice. Our data indicate that PPARbeta/delta governs glucose utilization and lipoprotein metabolism and has an important anti-inflammatory role in liver. Overall, our analysis reveals divergent roles of PPARalpha and PPARbeta/delta in regulation of gene expression in mouse liver.

MeSH terms

  • Animals
  • Gene Deletion
  • Gene Expression Profiling*
  • Gene Expression Regulation*
  • Immunity / genetics
  • Inflammation / genetics
  • Liver / metabolism*
  • Metabolome / genetics
  • Mice
  • Oligonucleotide Array Sequence Analysis
  • PPAR alpha / deficiency
  • PPAR alpha / genetics
  • PPAR alpha / metabolism*
  • PPAR delta / deficiency
  • PPAR delta / genetics
  • PPAR delta / metabolism*
  • PPAR-beta / deficiency
  • PPAR-beta / genetics
  • PPAR-beta / metabolism*
  • Transcription, Genetic*

Substances

  • PPAR alpha
  • PPAR delta
  • PPAR-beta