Fine Particulate Matter (PM_2.5) upregulates expression of Inflammasome NLRP1 <i>via</i> ROS/NF-κB signaling in HaCaT Cells

Abstract

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.