Original ContributionRedox regulation of mitophagy in the lung during murine Staphylococcus aureus sepsis
Section snippets
Materials
Antibodies were purchased as follows: heme oxygenase 1 (HO-1; Assay Designs), Beclin-1 (Cell Signaling), Nrf2 (Santa Cruz), p62 (Abcam), LC3 (Sigma–Aldrich), SOD2 (Abcam), 8-hydroxy-2-deoxyguanosine (8-OHdG; Genetex). Primers used for quantitative real-time reverse transcriptase polymerase chain reaction (qRT-PCR) were all obtained from Life Technologies (Atg5, Atg12, Beclin-1, interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α), SOD2, HO-1). Bafilomycin A1 (BFA) was purchased from LC
Pulmonary inflammation and oxidative stress during sepsis
To assess the pulmonary inflammatory responses to S. aureus peritonitis, we measured lung mRNA levels for the early phase proinflammatory cytokines IL-1β and TNF-α at 0, 6, 24, and 48 h. The IL-1β and TNF-α mRNA levels increased sharply at 24 to 48 h after clot implantation (Figs. 1A and B). Cellular inflammation was also greatly increased as shown by significantly elevated bronchoalveolar lavage (BAL) white blood cell count and BAL protein at 24 h (Figs. 1C and D). To indirectly measure levels of
Discussion
Our data demonstrate for the first time that S. aureus sepsis induces mitophagy in the distal lung by a redox-sensitive pathway. Moreover, this redox pathway plays a key role in intracellular mitochondrial quality control, specifically in the turnover of damaged mitochondria as well as in mitochondrial biogenesis. In our mouse model, we found increased early phase inflammatory cytokine elaboration in the lung, i.e., IL-1β and TNF-α, as well as evidence of end organ inflammation and ALI
Acknowledgment
The authors thank the Duke Center for Hyperbaric Medicine and Environmental Physiology as well as the Eugene E. Stead Foundation for their generous scholarships and support.
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