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Fig. 2
(A) Percentage of growth of the S. aureus strains containing the empty vector (pSD1) or the ppnK knockdown strain (NADK sgRNA) at time 0, and 1, 2, 4, and 6 hpi of RAW264.7 macrophages left untreated or treated with N-acetylcysteine (NAC). Bars indicate standard errors of the means of biological replicates (n=4). Comparison of data was performed using two-ways analysis of variance (*p<0.05, **p<0.01, ****p<0.0001). (B–C) Representative images of RAW264.7 macrophages infected with S. aureus/pSD1 or S. aureus/NADK sgRNA strains and analyzed 6 hpi by confocal fluorescence microscopy using antibodies to label S. aureus (Cy5, red) and LAMP-1 (FITC, green). Nuclei were labeled with DAPI (blue). (B) shows untreated macrophages. (C) shows macrophages treated with NAC. Insets are shown at higher magnification. Images are representative of three independent experiments. (D) Cell death of RAW264.7 macrophages uninfected (NI), uninfected and treated with Triton X-100 (lysis control), or 6 hpi with S. aureus strains containing the empty vector (pSD1) or the ppnK knockdown strain (NADK sgRNA). Bars indicate standard errors of the means of biological replicates. Comparison of data was performed using two-ways analysis of variance (*p<0.05, **p<0.01, ****p<0.0001). Data are representative of at least three independent experiments.
Nicotinamide adenine dinucleotide kinase (NADK) promotes S. aureus survival and cytotoxicity in macrophages.