Mycophenolic acid inhibits oleic acid-induced vascular smooth muscle cell activation by inhibiting cellular reactive oxygen species

BACKGROUND. Vascular smooth muscle cell (VSMC) proliferation and matrix protein accumulation play important roles in the development and progression of chronic allograft vasculopathy. Mycophenolic acid (MPA) inhibits various types of mesenchymal cell proliferation and cellular reactive oxygen species (ROS) are involved in the anti-proliferative effect of MPA. In this study, we investigated the effects of MPA on oleic acid (OA)-induced VSMC proliferation and the role of ROS in this process. METHODS. Primary VSMCs from Sprague-Dawley rats were stimulated with 100 μM OA, with or without MPA (0.1- 10 μM) or 5 mM N-acetylcysteine (NAC) for one hour prior to the addition of OA. Cell proliferation was measured by methylthiazoletetrazolium (MTT) assays, proliferating cell nuclear antigen (PCNA) expression, and fibronectin secretion by Western blot analysis, and dichlorofluorescein (DCF)-sensitive cellular ROS by fluorescence-activated cell scanning (FACS). RESULTS. OA (100 μM) increased cell proliferation, as measured by MTT (by 1.6-fold), PCNA expression, fibronectin secretion, and cellular ROS (by 1.6-fold). Treatment with MPA dose-dependently inhibited OA-induced VSMC proliferation, fibronectin secretion, and cellular ROS. Treatment with 5 mM NAC also inhibited OA-induced rat VSMC activation. CONCLUSIONS. These results suggest that MPA inhibits OA-induced VSMC proliferation and matrix protein synthesis partially by inhibiting cellular ROS.