Characterization and mechanistic regulation of the Bovine inflammasome.

Inflammasomes, intracellular multi-protein complexes, sense cytosolic danger signals, leading to the initiation and amplification of inflammation via the maturation of the pro-inflammatory cytokine IL-1β and the induction of inflammatory cell death. Different inflammasomes recognize distinct danger signals and pathogens, which is crucial for both physiological immunity and therapeutic targeting. Although inflammasomes have been studied extensively in humans and mice, research in cattle remains limited. In this study, bovine peripheral blood monocytes (PBMC) were treated with various stimuli and inhibitors of several inflammasomes, and mature IL-1β secretion was measured as a readout of inflammasome activation. Bovine PBMC responded to all the test stimuli in a dose-dependent manner, promoting IL-1β secretion. Inhibitor assays showed that bovine NLRP3 and non-canonical inflammasome activation were similar to those in mice, whereas flagellin- and dsDNA-mediated activation was uniquely inhibited by the potassium efflux inhibitor glibenclamide and the NLRP3-specific inhibitor MCC950. In contrast to murine responses, Staphylococcus aureus induced inflammasome activation in bovine PBMC was entirely dependent on NLRP3. Although bovine PBMC responded normally to a broad range of known inflammasome stimuli, their activation mechanisms differ from those of mice, relying predominantly on NLRP3, which was consistently inhibited by MCC950. These findings offer novel insights into the bovine inflammasome biology and may contribute to the understanding of inflammasome-related diseases in cattle.