Fig. 8.

Confocal immunofluorescence micrographs of the alveolar region pre-/post-S. aureus inoculation. A and B: confocal micrograph of lung alveolar sections stained for LC3II (red), citrate synthase (green), and TTF1 (magenta, AT₂ cells), nuclei are counterstained with DAPI. Arrows denotes overlay of LC3 and citrate synthase (yellow/orange florescence). A: control lung section showing a macrophage with few LC3 puncta. B: section from day 2 lung showing increased citrate synthase expression and LC3 puncta in AT₂ cells and macrophages. C and D: confocal micrographs of lung sections stained for Pink1 (red), citrate synthase (green), and TTF1 (magenta, AT₂ cells), and nuclei are counterstained with DAPI. Arrows denote overlay of Pink1 and citrate synthase (yellow/orange florescence). C: control lung section showing few Pink1 puncta colocalized with mitochondria. D: pneumonia section shows increased citrate synthase on day 2 colocalized with Pink1 (yellow/orange florescence) in AT₁, AT₂, and mononuclear cells. Arrows denotes overlay of Pink1 and citrate synthase implying that S. aureus pneumonia stimulates Pink1 colocalization to mitochondria. E and F: confocal micrograph of lung alveolar sections stained for Parkin (Park2) (red), citrate synthase (green), and NRF-1 (magenta, nuclear translocation in both AT₂ and macrophage cells), nuclei are counterstained with DAPI. E: control lung section shows little Parkin colocalized with mitochondria. F: lung section on day 2 shows increased citrate synthase colocalized with Parkin (yellow/orange fluorescence). Postinoculation, nuclear NRF-1 is seen in AT₂ cells (pink nuclei) but not in macrophages (arrows) consistent with mitochondrial biogenesis. Localization of Parkin with citrate synthase is seen both in AT₂ cells (displaying nuclear NRF-1) and macrophages (blue nuclei) showing mitochondrial QC induction by pneumonia. Magnification = ×1,000. Data are representative of 3 sets of mice.