Fig 1: SAK promotes NLRP3 inflammasome-related gene transcription and cytokine release in CA-SA pneumonia.a–i 2 × 108 CFU of S. aureus was pipetted into the nares of anesthetized C57BL/6 wild-type mice. Bronchoalveolar lavage fluid (BALF) was taken 48 h after infection of mice, and total RNA was extracted from lung tissue at the same time. a GSEA analysis identified cytokine related genes (IFN-α, IFN-γ, IL-6, IL-1), complement related genes and NLRP3 inflammasome pathway enrichment in the ST398-WT infected mice. b The level of mouse plasma cytokine was detected by Bio-Plex Pro Mouse Cytokine 23-plex Assay. The data were normalized by the Z score according to the standard deviation from the mean. c Cytokine levels in mouse BALF were detected by BD Cytometric Bead Array (CBA) Mouse Th1/Th2/Th17 Cytokine Kit (n = 4). Unpaired t test was used for statistical analyses after Shapiro–Wilk normality test and data are presented as mean ± SD. d Detection of IL-1β in mouse BALF by ELISA (n = 4). Unpaired t test was used for statistical analyses after Shapiro–Wilk normality test and data are presented as mean ± SD. e Comparison of the expression levels of NLRP3 inflammasome activation-related molecules between the two groups. The data were normalized by the Z score according to the standard deviation from the mean. f–i qRT-PCR analysis of Nlrp3, Caspase-1, IL-1β, and IFN-α in the lung tissues of wild-type or sak deletion mutants infected mice. Relative mRNA levels were calculated using β-actin as control and expressed as 2^(-ΔΔCt). Unpaired t test was used for statistical analyses after Shapiro–Wilk normality test and data are presented as mean ± SD. See Supplementary methods for the abbreviated list of cytokines or genes in Fig. 3b, e. *p < 0.05, ** p < 0.01.