Knockout of the Sr-a1 gene abolished the up-regulation of macrophage phagocytosis by ozone. (IMAGE)
Caption
Knockout of the Sr-a1 gene abolished the up-regulation of macrophage phagocytosis by ozone. A: The protein levels of SR-A1 of BMDMs from the wild-type (WT) mice or Sr-a1−/− mice were detected by Western blotting (n = 3). B–D: BMDMs from the WT mice or Sr-a1−/− mice were induced to M1 type with LPS (100 ng/mL) and IFN-γ (50 ng/mL) for 24 h after differentiation and maturation in vitro. LPS (1 μg/mL) was used to stimulate BMDMs for 12 h to induce inflammation. Prior to this, BMDMs were pretreated with ozone (15 μg/mL) for 2 h, or with AICAR (300 μmol/L) or Compound C (20 μmol/L) for 15 min. Stained-labeled NETs (orange) were incubated with BMDMs processed as above in the confocal dish for 15 min, then rinsed lightly with ice-cold PBS three times, and photographed under confocal microscopy (B and C). NETs were labeled by Sytox Orange (n = 3). Scale bar, 50 μm. The protein levels of p-AMPK/AMPK in BMDMs (from WT mice) were detected by Western blotting (n = 3; D). E: The schematic illustration indicates that ozone enhances phagocytosis of NETs by macrophages through upregulation of SR-A1 via the AMPK pathway to alleviate septicemic lung injury. Data are presented as mean ± standard deviation. **P < 0.01 and ***P < 0.001 by one-way ANOVA followed by Tukey's tests for multiple comparisons. Abbreviations: CC, Compound C; SR-A1, scavenger receptor A1; AMPK, AMP-activated protein kinase; NETs, neutrophil extracellular traps; DAMPs, damage-associated molecular patterns; TF, tissue factor; MMP-9, matrix metalloproteinase-9; IL-1β, interleukin-1β; LPS, lipopolysaccharide; TLR4, Toll-like receptor 4; ns, not significant.
Credit
Journal of Biomedical Research
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