Figure 1.

Mevalonate cascade inhibition induces cell death in primary myocardial atrial fibroblast. (a) Cells were treated with simvastatin (5, 10, 15 or 20 μM) and cell viability was assessed 48 and 96 h thereafter by MTT assay. Control cells for each time point were treated with the solvent control (DMSO). Results are expressed as percentage of corresponding time point control and represent the mean±S.D. of nine independent experiments in three different of patient myocardial atria fibroblast (***P<0.001). (b and c) Effects of supplementation with 2.5 and 5 mM mevalonate on cell viability (MTT Assay) (b) and cell morphology (c), to treatment with simvastatin (10 μM, 48 and 96 h) on simvastatin-induced cell death. Cells were pretreated with indicated concentration of mevalonate (4 h) and then co-treated with simvastatin (10 μM, 48 and 96 h). For each experiment control cells were treated with simvastatin and mevalonate solvent (DMSO and ethanol) alone. Results are expressed as mean±S.D. of nine independent experiments using three different myocardial atrial fibroblast primary cells (***P<0.001). (d) Effects of supplementation with cholesterol (0–50 μM) on cell viability (MTT Assay), with simvastatin (10 μM, 48 and 96 h). Cells were pretreated with indicated concentration of cholesterol (4 h) and then co-treated with simvastatin (10 μM, 48 and 96 h). For each experiment control cells were treated with simvastatin and cholesterol solvent (DMSO and ethanol) alone (control) or with both. Results are expressed as mean±S.D. of nine independent experiments using three different myocardial atrial fibroblast primary cells (NS, non significant). (e) Time course of simvastatin (10 μM) on the abundance of RhoA, RohC and Rac1/2/3 and in membrane and cytosolic fractions obtained from myocardial fibroblast (western blot). Presence of pan-Cadherin was used to normalize for loading of membrane fractions. Data are typical of two independent experiments using different primary cultures