Rosiglitazone effects on kidney gene expression

Thiazolidinediones increase tissue insulin sensitivity and are protective against worsening of nephropathy and hypertension in diabetes. Mechanisms underlying protection at the renal level likely involve a variety of unknown changes in gene expression. We examined kidney gene expression in obese and lean Zucker rats in response to rosiglitazone (Avandia®), a peroxisome proliferator activated receptor (gamma-subtype) agonist. Lean and obese Zucker rats were treated with either control chow or chow with added rosiglitazone (3 mg/kg•bw) for 12 weeks (n = 3/group). Total kidney mRNA expression was evaluated using the Affymetrix Rat Genome 230 2.0 GeneChip. 903 probe sets were significantly (P < 0.05) altered with at least 1.5-fold changes between groups. In untreated obese rats, 300 probe sets were increased and 244 decreased, relative to lean. Increased genes included the β-subunit of the epithelial sodium channel (ENaC), the thiazide-sensitive Na-Cl cotransporter, and aquaporin 3. Decreased genes included angiotensin converting enzyme, type 1 (ACE1). FatiGO analysis showed that the highest number of altered genes between lean and obese belonged to the categories: ion binding, hydrolase activity, and protein binding. RGZ increased expression of uncoupling protein 1 (UCP1), CD36, and fatty acid binding protein 4 (FAbp4) in both lean and obese rats. In obese rats, 33 genes were normalized by RGZ (no longer different from lean) including ACE1, fatty acid synthase (Fasn), and stearoyl-coenzyme A desaturase 2 (Scd2). Ingenuity Pathways System analysis of genes upregulated by RGZ in obese rats revealed two major nodes affected: PPAR-gamma and tumor necrosis factor alpha (TNF-alpha). Keywords: Thiazolidinediones, PPAR-gamma agonists, renal, type II diabetes, obesity Twelve male Zucker rats (6 Lean and 6 Obese) were used in the study. Three rats from each body type were fed either with control diet (ground chow diet) or control diet with rosiglitazone (3 mg/kg body weight). The rats were weighed weekly and fed diets and recieved water ad libitum for 12 weeks.