Fine Particulate Matter (PM(2.5)) upregulates expression of Inflammasome NLRP1 via ROS/NF-κB signaling in HaCaT Cells

Skin, as the major organ of a human body, is constantly exposed to PM(2.5) stimulation, which may exert specific toxic influences on the physiology of skin. This study aims to investigate the effect of PM(2.5) on the formation of inflammasomes in skin cells and to explore the potential mechanism linking PM(2.5) and skin inflammation. Changes in mRNA and protein levels of inflammasome-related genes were detected by real-time PCR and western blot in human immortalized epidermal cells (HaCaT) treated with PM(2.5) at multiple concentrations for 24 hours. The expression of NLRP1 was increased significantly both in mRNA and protein levels after PM(2.5) exposure while the elevated secretory protein level of IL-1β in cell culture was detected by ELISA, which is one of the main downstream factors of NLRP1. In addition, the upregulation of NLRP1 and IL-1β could be reversed by NF-κB inhibitor indicating that PM(2.5) may promote NLRP1 expression through activating NF-κB pathway. Furthermore, high ROS level was also found in cells treated with PM(2.5) and inhibition of ROS could also reverse NK-κB production stimulated by PM(2.5) that means ROS is involved in this skin inflammation process.