Deoxynivalenol induces pyroptosis and IL-1β secretion via P2X7R signal in murine RAW264.7 macrophages

Deoxynivalenol (DON), a trichothecene mycotoxin, exerts pro-inflammatory and immunomodulatory activity. Interleukin (IL)-1β serves a crucial part as a gate keeper of inflammation in DON-induced macrophages, but an overview of how DON exposure elicits IL-1β secretion from RAW264.7 cells has not been fully illustrated. Here we found that the cellular phenomenon, involved with a type of programmed cell death known as pyroptosis, contains: 1) increase of pro-IL-1β expression, 2) motivation of caspase-1, 3) caspase-1-dependent maturement of IL-1β, 4) caspase-1 fragmentation of gasdermin D (GSDMD), and 5) IL-1β secretion through GSDMD pore. Mechanistically, the present study certified that DON both as first and second signals engaged in IL-1β release is mediated by purinergic P2X7 receptor (P2X7R)-Src signaling. During this process, P2X7R signal is required for GSDMD pore forming course in ASC-independent manner. Moreover, blocking of K⁺ efflux, ROS formation, as well as cathepsin B activity decreases IL-1β export. Our data show that exposure to DON does cause pyroptosis and IL-1β secretion via P2X7R signal in RAW264.7 macrophages. Overall, these results provide new mechanistic clue for DON as a pro-inflammatory factor in innate immune signaling events.