Inflammasomes and DNA Damage Orchestrate Divergent Pyroptotic Fates in Neutrophils

The understanding of pyroptotic cell death and its mechanistic insights in neutrophils remains less explored and ambiguous. This study analyzes neutrophil pyroptotic responses under different conditions and dissects distinct pyroptosis-associated events, including IL-1β release and cell death. We decipher the signalling pathways underlying these responses and distinguish them from other cell death mechanisms. Interestingly, we observe IL-1β release and enhanced survival in neutrophils in response to LPS-primed ATP-treatment, in contrast to a combination of IL-1β release with cell death in macrophages. While LPS-primed nigericin-treated neutrophils exhibit IL-1β release and cell death, characterized by nuclear rounding, cell swelling/ ballooning, plasma membrane pore formation, and subsequent cell rupture, confirming the occurrence of pyroptotic cell death. While nigericin alone triggers cytokine uncoupled pyroptosis. Intriguingly, these phenomena do not induce under other death programs, including apoptosis, NETosis. This provides opportunity to unravel the regulation of these pyroptotic responses in neutrophils. Data observed reveal the role of NLRP3 and context-dependent caspase -1 & 11 in IL-1β secretion. While, DNA damage and caspase-7 & 9 regulate pyroptotic death. Intriguingly, forced DNA damage by ATM kinase inhibitor mitigated inflammasome activation and IL-1β release, while spur death. Furthermore, this study identifies perinuclear actomyosin forces driving nuclear rounding and pyroptotic death. Both murine neutrophils exposed to bacteria and human neutrophils treated with nigericin exhibit these pyroptotic processes, highlighting their broad relevance. This study depicts decision whether to secrete cytokines or undergo pyroptotic cell death emphasizing the regulatory role of DNA damage-cytoskeletal axis beyond inflammasome activation. Moreover, LPS and bacteria induced acute lung injury in mice displays nuclear rounding presenting pyroptotic neutrophils and enhanced NLRP3, Caspase-11 activation, and IL-1β release. Together, this study defines intriguing crosstalk of NLRP3, caspases, DNA damage, and actomyosin forces that orchestrate divergent inflammatory fates, potentially leading to opportunities for targeted strategies for combating inflammation.