Troglitazone Induces Extracellular Matrix and Cytoskeleton Remodeling in Mouse Collecting Duct Cells

Abstract

Peroxisome proliferator-activated receptor (PPARγ) has been shown to have a protective role in the nephron through its ability to inhibit a transforming growth factor- (TGF-β) mediated fibrotic response. In contrast, PPARγwas also shown to induce a mesenchymal transformation in epithelial intestinal cells. A fibrotic response in the collecting duct has only recently been established; however, the entire collecting duct has not been fully examined. Inner medullary collecting duct cells (IMCD-K2) and mouse cortical collecting duct cells (M1), representing the cortical and medullary collecting duct, were exposed to 5–10 μM troglitazone for 24 hours. Troglitazone resulted in an elongated morphology, 60% decreases in E-cadherin andβ-catenin, a 35% decrease inα-catenin, and a 1.5-fold increase in fibronectin. These effects were not reversed with PPARγantagonists or affected with PPARγoverexpression. Our results indicate that troglitazone induced a mesenchymal-like transformation in M1 and IMCD-K2 epithelial cells independently of PPARγ.