Gene expression changes in mouse aorta during activation of or interference with PPAR gamma signaling.. Mus musculus

Ligand-mediated activation of the nuclear hormone receptor PPAR gamma lowers blood pressure and improves glucose tolerance in humans. Two naturally occurring mutations (P467L, V290M) in the ligand binding domain of PPAR gamma have been described in humans that lead to severe insulin resistance and hypertension. Experimental evidence suggests that these mutant versions of PPAR gamma act in a dominant negative fashion. To better understand the molecular mechanisms underlying PPAR gamma action in the vasculature, we determined the gene expression patterns in mouse aorta in response to activation or interference with the PPAR gamma signaling pathway. Keywords: time course, dose response Overall design: To assess the response to PPAR gamma interference, we used adult mice containing a dominant negative form of PPAR gamma. These mice have a targeted P465L mutation, which is equivalent to the P467L mutant, described in human patients. Wild-type littermates were used as the genetic control. The PPAR gamma signaling pathway was activated by administration of rosiglitazone for either 2 or 14 days to adult mice (C57BL/6J strain) at a dose of 3 or 10 mg/kg/day via the food. Control mice were fed standard mouse chow. For the microarray hybridizations, 2-3 biological replicates from each experimental group were used. Biological replicates were RNA pooled from 8 different mouse aortas. All the microarray procedures were conducted at the University of Iowa DNA Core facility using standard Affymetrix protocols. In brief, approximately 3 ug of total RNA was used as input to a one-step amplification procedure to generate biotin-labeled RNA fragments for hybridization to the Affymetrix GeneChip Mouse Genome 430 2.0 array.