Rosuvastatin Inhibits the Apoptosis of Platelet-Derived Growth Factor-Stimulated Vascular Smooth Muscle Cells by Inhibiting p38 via Autophagy.

Abstract

The secretion of platelet-derived growth factors (PDGFs) into vascular smooth muscle cells (VSMCs) induced by specific stimuli, such as oxidized low-density lipoprotein (LDL) cholesterol, initially increases the proliferation and migration of VSMCs, and continuous stimulation leads to VSMC apoptosis, resulting in the formation of atheroma. Autophagy suppresses VSMC apoptosis, and statins can activate autophagy. Thus, this study aimed to investigate the mechanism of the autophagy-mediated vasoprotective activity of rosuvastatin, one of the most potent statins, in VSMCs continuously stimulated with PDGF-BB, a PDGF isoform, at a high concentration (100 ng/ml) to induce phenotypic switching of VSMC. Rosuvastatin inhibited apoptosis in a concentration-dependent manner by reducing cleaved caspase-3 and interleukin-1β (IL-1β) levels and reduced intracellular reactive oxygen species (ROS) levels in PDGF-stimulated VSMCs. It also inhibited PDGF-induced p38 phosphorylation and increased the expression of microtubule-associated protein light chain 3 (LC3) and the conversion of LC3-I to LC3-II in PDGF-stimulated VSMCs. The ability of rosuvastatin to inhibit apoptosis and p38 phosphorylation was suppressed by treatment with 3-methyladenine (an autophagy inhibitor) but promoted by rapamycin (an autophagy activator) treatment. SB203580, a p38 inhibitor, reduced the PDGF-induced increase in intracellular ROS levels and inhibited the formation of cleaved caspase-3, indicating the suppression of apoptosis. In carotid ligation model mice, rosuvastatin decreased the thickness and area of the intima and increased the area of the lumen. In conclusion, our observations suggest that rosuvastatin inhibits p38 phosphorylation through autophagy and subsequently reduces intracellular ROS levels, leading to its vasoprotective activity. SIGNIFICANCE STATEMENT: This study shows the mechanism responsible for the vasoprotective activity of rosuvastatin in vascular smooth muscle cells under prolonged platelet-derived growth factor stimulation. Rosuvastatin inhibits p38 activation through autophagy, thereby suppressing intracellular reactive oxygen species levels, leading to the inhibition of apoptosis and reductions in the intima thickness and area. Overall, these results suggest that rosuvastatin can be used as a novel treatment to manage chronic vascular diseases such as atherosclerosis.