Background: Peroxisome proliferator activator receptor-gamma (PPARgamma) is a member of the nuclear receptor superfamily. Ligands of PPARgamma, thiazolidione derivatives, have been reported to be the one of the candidates for the treatment of inflammatory bowel disease (IBD). Given the fact that PPARgamma is a transcription regulator, expression pharmacogenomics, including differential gene expression profiling of drug responses in a colitis model, is thought to be a useful approach for finding relevant genes that can serve as the target for new drug treatment of IBD.
Methods: We performed a global analysis for differential gene expression of the intestine in a dextran sodium sulfate (DSS) colitis mouse model following PPARgamma ligand administration. By applying a high-density oligonucleotide array method, the expression patterns of approximately 12000 genes were analyzed, and selected genes were confirmed by a real-time quantitative PCR method.
Results: The analysis of downregulated genes in the DSS mice following PPARgamma administration revealed several functional gene clusters with altered expression: (1) oncogene families such as GRO1 oncogenes, (2) inflammatory mediator-related genes such as the interferon-gamma gene, (3) water electrolyte-associated genes, and (4) others.
Conclusions: This is the first demonstration of global gene expression analysis using the DSS colitis mouse model with a PPARgamma ligand, and these results provide new insight for finding novel target genes for treating IBD.