Inhibition of ARC promoting the apoptosis of rat pulmonary arterial smooth muscle cells after serum deprivation in vitro

: Apoptosis has important pathophysiological consequences contributing to pulmonary arterial hypertension (PAH). However, the mechanism underlying apoptosis in PAH remains unknown. Apoptosis repressor with caspase recruitment domain (ARC) is an essential factor in cell apoptosis, and regulates intrinsic and extrinsic apoptosis signaling pathways. It is hypothesized that ARC may be involved in the apoptotic responses of pulmonary arterial smooth muscle cells (PASMCs) following mild chronic injury. In the present study, serum deprivation (SD) was used to induce apoptosis of PASMCs. It was demonstrated that the expression of ARC in PASMCs was significantly increased following SD stimulation within 24 h, and ARC downregulation using small interfering RNA significantly enhanced the apoptosis of PASMCs following SD stimulation. In addition, the results demonstrated that ARC downregulation significantly increased the expression of proapoptotic factors and the level of reactive oxygen species (ROS), and decreased the mitochondrial membrane potential following SD exposure, suggesting ARC regulates the apoptosis of PASMCs via modulating mitochondrial function and ROS accumulation. The results of the present study revealed that ARC inhibition promotes the apoptosis of PASMCs following SD stimulation, and that ARC expression increases in the early stages of SD injury.