SLPI suppresses ATP-mediated release of IL-1β from human monocytes – evidence for a novel anti-inflammatory mechanism

Background: IL-1β is a multifunctional pro-inflammatory cytokine associated with diverse inflammatory disorders. IL-1β release requires two consecutive danger signals. LPS is a prototypical first signal inducing pro-IL-1β synthesis, whereas extracellular ATP is a typical second signal triggering inflammasome activation, proteolytic cleavage of pro-IL-1β by activated caspase-1, and release of mature IL-1β. Secretory leukocyte protease inhibitor (SLPI), in addition to its well-known function as major anti-protease of the lung, possesses potent anti-microbial and anti-inflammatory properties. Here, we test the hypo…