SGK1 inhibits PM2.5-induced apoptosis and oxidative stress in human lung alveolar epithelial A549 cells

Emerging evidence demonstrated that particulate matter 2.5 (PM2.5) is an important environmental risk factor for lung diseases. Serum- and glucocorticoid-inducible kinase 1(SGK1) was reported to be a crucial factor for cell survival. However, the role of SGK1 in PM2.5-induced cell injury is still unclear. In this work, we firstly found that the expression of SGK1 was decreased in PM2.5-treated human lung alveolar epithelial (A549) cells by western blot. In addition, overexpression of SGK1 significantly attenuated A549 cell apoptosis and reduced the reactive oxygen species (ROS) generation induced by PM2.5. Moreover, we found that PM2.5 exposure significantly promoted the ERK1/2 activation and inhibited the AKT activation, whereas overexpression of SGK1 could reverse that. Finally, the results of the rescue experiment showed that MK2206 (AKT inhibitor) could rescue the impact of SGK1 on A549 cell apoptosis, while PD98059 (ERK1/2 inhibitor) could not further aggravate the impact. Taken together, our results suggest that SGK1 inhibits PM2.5-induced cell apoptosis and ROS generation via ERK1/2 and AKT signaling pathway in human lung alveolar epithelial A549 cells.