WWC1 deficiency exacerbates sepsis-induced lung injury by promoting NETosis, M1 and M2b macrophage recruitment, and pyroptosis via YAP1 and STING pathways.

backgroundOur recent investigations have shown that WWC1 loss leads to sepsis-induced lung injury (SiLI) by reducing activation of Yes-associated protein 1 (YAP1) and stimulator of interferon genes (STING) pathways. This study further explores the involvements of pyroptosis, NETosis, and macrophage recruitment in the associated events.

methodsWild-type (wt) C57BL/6 mice, or mice with WWC1 gene knockout (WWC1-ko) or knock-in (WWC1-ki), were subjected to cecal ligation and puncture for SiLI modeling. Immunofluorescence staining and western blot (WB) were employed to analyze NETosis-related markers in lung tissues. Flow cytometry was employed to analyze the proportions of neutrophils and macrophages in bronchoalveolar lavage fluid (BALF). Immunohistochemistry and WB were applied to analyze pyroptosis markers. Histological staining was performed to analyze inflammatory responses in the lung tissues. Specific antagonists or agonists were utilized to analyze the involvements of YAP1 and STING in the inflammatory cascades.

resultsWWC1-ko mice showed more pronounced NETosis in the lung, accompanied by increased recruitment of neutrophils and macrophages, particularly M1 and M2b subtype macrophages, in the BALF. The pro-pyroptotic cascade was also activated in the lung of WWC1-ko mice. Administration of specific antagonists of NLRP3, YAP1, STING, and IRF3 reduced pyroptosis, alleviated NETosis, reduced abundance of macrophages, and mitigated inflammatory damage in the lung of WWC1-ko mice. By contrast, WWC1-ki mice were more resistant to these inflammatory cascades, which were, however, diminished upon the artificial activation of YAP1 or STING.

conclusionThe activation of pyroptosis, YAP1, and STING cascades upon WWC1 deficiency contributes to NETosis and accumulation of pro-inflammatory immune cells in SiLI.