Jeb S Clark1, Anthony J Carter2, Mehul Dixit2, Istvan Arany3. 1. Department of Internal Medicine, University of Mississippi Medical Center, Jackson, MS, U.S.A. 2. Department of Pediatrics, Division of Pediatric Nephrology, University of Mississippi Medical Center, Jackson, MS, U.S.A. 3. Department of Pediatrics, Division of Pediatric Nephrology, University of Mississippi Medical Center, Jackson, MS, U.S.A. iarany@umc.edu.
Abstract
BACKGROUND/AIM: Studies have shown that simvastatin (SIM) inhibits epithelial-mesenchymal transition (EMT), a key step in fibrosis, and activates the anti-fibrotic heme oxygenase-1 (HO-1) gene in renal proximal tubule cells independent of its lipid-lowering. We tested the hypothesis that SIM inhibits EMT via HO-1-dependent suppression of reactive oxygen species (ROS) release. MATERIALS AND METHODS: Renal proximal tubule cells were treated with either 10 μM SIM or 10 ng/ml transforming growth factor-β1 (TGFβ1) or with their combination and promoter activity of the alpha-smooth muscle actin (α-SMA) gene, stress fiber formation (markers of EMT), as well as ROS production were determined. HO-1 was manipulated via genetic and pharmacologic means. RESULTS: SIM prevented TGFβ1-dependent EMT and ROS production. Inhibition/knockdown of HO-1 reversed, while induction/overexpression of HO-1 emulated beneficial effects of SIM. CONCLUSION: SIM, via HO-1, suppresses TGFβ1-dependent ROS production and, hence, EMT. Further evaluation of the anti-fibrotic nature of SIM in the kidney would be useful in the treatment of chronic kidney disease.
BACKGROUND/AIM: Studies have shown that simvastatin (SIM) inhibits epithelial-mesenchymal transition (EMT), a key step in fibrosis, and activates the anti-fibrotic heme oxygenase-1 (HO-1) gene in renal proximal tubule cells independent of its lipid-lowering. We tested the hypothesis that SIM inhibits EMT via HO-1-dependent suppression of reactive oxygen species (ROS) release. MATERIALS AND METHODS: Renal proximal tubule cells were treated with either 10 μM SIM or 10 ng/ml transforming growth factor-β1 (TGFβ1) or with their combination and promoter activity of the alpha-smooth muscle actin (α-SMA) gene, stress fiber formation (markers of EMT), as well as ROS production were determined. HO-1 was manipulated via genetic and pharmacologic means. RESULTS: SIM prevented TGFβ1-dependent EMT and ROS production. Inhibition/knockdown of HO-1 reversed, while induction/overexpression of HO-1 emulated beneficial effects of SIM. CONCLUSION: SIM, via HO-1, suppresses TGFβ1-dependent ROS production and, hence, EMT. Further evaluation of the anti-fibrotic nature of SIM in the kidney would be useful in the treatment of chronic kidney disease.