IL-36G drives sepsis-induced lung injury via NF-κB-dependent activation of the NLRP3 inflammasome in macrophage pyroptosis.

BACKGROUND

Sepsis is a critical illness marked by widespread inflammation and failure of multiple organs. Pyroptosis and NLRP3 inflammasome activation play critical roles in sepsis pathogenesis. However, the involvement of interleukin-36 gamma (IL-36G) in this process remains unclear. This work probe to clarify the role and mechanism of IL-36G in sepsis-induced inflammation and lung injury.

METHODS

RAW264.7 macrophages were exposed to lipopolysaccharide (LPS) to construct an in vitro model of sepsis. Cell viability, pyroptosis, and inflammatory cytokine expression were assessed by CCK-8 assay, flow cytometry, qPCR, and Western blot. The NF-κB pathway and NLRP3 inflammasome activation were evaluated following IL-36G overexpression or knockdown, with or without the NF-κB inhibitor BAY 11-7085. In vivo, a cecal ligation and puncture (CLP)-induced sepsis model was used in IL-36G knockout mice to assess lung injury and inflammatory responses.

RESULTS

LPS stimulation induced pyroptosis and upregulated IL-36G expression in RAW264.7 cells, accompanied by increased levels of IL-6, IL-1β, TNF-α, and IL-18. IL-36G knockdown attenuated LPS-induced pyroptosis, inflammatory cytokine production, and expression of pyroptosis-related proteins. IL-36G overexpression activated the NF-κB pathway and enhanced NLRP3 inflammasome activation, while BAY 11-7085 inhibited these effects. In CLP-induced septic mice, IL-36G expression was upregulated, and its knockout improved survival, reduced the lung wet/dry (W/D) weight ratio, alleviated lung tissue damage, reduced inflammatory cytokine levels, and suppressed NF-κB-mediated NLRP3 inflammasome activation.

CONCLUSION

IL-36G promoted pyroptosis and NLRP3 inflammasome activation via NF-κB signaling pathway, contributing to sepsis-induced lung injury. Knockdown of IL-36G mitigated inflammation and tissue damage, indicating the therapeutic potential of IL-36G in sepsis.