Regulation on RhoA in Vascular Smooth Muscle Cells Under Inflammatory Stimulation Proposes a Novel Mechanism Mediating the Multiple-Beneficial Action of Acetylsalicylic Acid

Abstract

Recent studies have revealed the additional beneficial effects of acetylsalicylic acid (aspirin) in the medication of cardiovascular diseases. The small GTPase RhoA as an important signaling factor is implicated in a wide range of cell functions. This study aimed to investigate the regulatory effect of acetylsalicylic acid on RhoA in vascular smooth muscle cells (VSMCs). We found that aspirin at 300 μM suppressed VSMCs proliferation stimulated by LPS, and this inhibitory effect was partially mediated by inhibiting the iNOS/NO pathway. RhoA overexpression was downregulated by aspirin (both 30 and 300 μM) because of enhanced degradation of RhoA protein. The effect of LPS on increasing active RhoA level was significantly attenuated by aspirin (300 μM), which exerted no effect on RhoA translocation. The promoted RhoA phosphorylation under LPS stimulation, coupled with RhoA protein expression, was greatly decreased by aspirin treatment. No effect of aspirin was found on the expression, activation, and phosphorylation of RhoA in VSMCs devoid of inflammatory stimulation. Our investigation indicates that the regulation of RhoA by aspirin in VSMCs under inflammatory stimulus could be a novel mechanism via which aspirin, apart from the COX-dependent action, exerted the multiple beneficial effects.