Fig. 5.

Inhibition of the ETC Complex III, but not Complex I, increases the number of engulfed S. aureus.

After PMN exposure to S. aureus, neutrophil phagocytosis activities were assessed in neutrophils previously treated with mitochondrial inhibitors Antimycin A (1 μM, Complex III), myxothiazol (1 μM, Complex III), S3QEL (25 μM, Complex III), rotenone (1 μM, Complex I), an NADPH oxidase inhibitor apocynin (300 μM), or vehicle (DMSO). A) Representative image series of vehicle- or inhibitor-treated neutrophils exposed to GFP-labelled S. aureus. Samples were imaged for 30 min post-inoculation with S. aureus, and the area of GFP-S. aureus per neutrophil were quantified. One tile from a 5 × 5 image is shown for each condition. Immunofluorescence labelling: Mitochondria (MitoTracker Deep Red-red), bacteria (green), nuclei (blue); Magnification – 63X; Zoom – 2X; Scale bar – 15 μm. B) Quantification of S. aureus per neutrophil, expressed as relative area of GFP signal detected inside intact PMN. Data are mean ± SEM of n = 6–7 patients; p values indicated; mixed effects analysis with Dunnett post-test. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)