Fluvastatin protects vascular smooth muscle cells against oxidative stress through the Nrf2-dependent antioxidant pathway

Objective: HMG-CoA reductase inhibitors (statins) have pleiotropic actions, including the ability to reduce vascular oxidative stress. Transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) is an important regulator of cellular oxidative stress. This study examined the role of Nrf2 in statin-mediated antioxidant effects in vascular smooth muscle cells. Methods and results: In cultured human coronary artery smooth muscle cells (hCASMCs), fluvastatin activated the nuclear translocation of Nrf2, as evaluated by Western blotting and immunocytochemical analyses. Nrf2-antioxidant response element (ARE) activity was measured with a luciferase assay after transfection of reporter plasmids containing AREs. Fluvastatin significantly increased the transcriptional activity of the ARE. Electromobility shift assays using an ARE probe detected a complex that was significantly increased in intensity by fluvastatin. Western blotting and luciferase assay revealed fluvastatin activated Nrf2 via the PI3K/Akt pathway. Statins upregulated the Nrf2-related antioxidant genes heme oxygenase-1, NAD(P) H quinone oxidoreductase-1, and glutamate-cysteine ligase modifier subunits. Inhibition of Nrf2 by siRNA reduced statin-induced upregulation of these antioxidant genes. Moreover, Nrf2 siRNA markedly reduced the cytoprotective effects of fluvastatin against H2O2 administration in hCASMCs. Conclusions: Fluvastatin exerts cytoprotective effects against oxidative stress, inducing antioxidant genes through Nrf2/ARE in hCASMCs. These results suggest that the Nrf2/ARE pathway plays an important role in the regulation of statin-mediated antioxidant effects in vascular smooth muscle cells. (C) 2010 Published by Elsevier Ireland Ltd.