Objective To observe the role of caspase recruitment domain 9 (CARD9) gene signaling pathway in the effect of fine particulate matters (PM2.5) on peritoneal macrophages.
Methods Macrophages were extracted through intraperitoneal injection of serum-free medium from CARD9-/-or C57BL/6 female mice aged 6-8 weeks. The peritoneal macrophages were treated with 50, 100, and 200μg/mL PM2.5. After 24h PM2.5 exposure, cell viability and phagocytic capacity were measured. The expression levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in macrophage culture supernatant were determined along with the mRNA relative expression of Dectin-1, IL-6, and TNF-α in macrophages.
Methods Macrophages were extracted through intraperitoneal injection of serum-free medium from CARD9-/- or C57BL/6 female mice aged 6-8 weeks. The peritoneal macrophages were treated with 50, 100, and 200μg/mL PM2.5. After 24h PM2.5 exposure, cell viability and phagocytic capacity were measured. The expression levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in macrophage culture supernatant were determined along with the mRNA relative expression of Dectin-1, IL-6, and TNF-α in macrophages.
Results After 24 h PM2.5 exposure, the cell viability of macrophages in the 50, 100, and 200 μg/mL PM2.5 groups decreased to 93.35%, 90.89%, and 84.44% in C57BL/6 mice, and 95.30%, 92.23%, and 86.04% in CARD9-/- mice; there were no differences between C57BL/6 mice and CARD9-/- mice. PM2.5 induced increases of IL-6 and TNF-α in macrophages of C57BL/6 mice, which were (14.95±5.84) μg/L and (144.34±35.75) μg/L in the 50 μg/mL PM2.5 group, (30.55±2.34) μg/L and (228.93±46.62) μg/L in the 100 μg/mL group, and (47.90±9.90) μg/L and (351.38±46.82) μg/L in the 200 μg/mL PM2.5 group. For the same PM2.5 exposure dose, the concentrations of IL-6 and TNF-α in the macrophages of CARD9-/- mice were significantly lower than those of C57BL/6 mice (P < 0.05), except the IL-6 of the 50 μg/mL PM2.5 group. The mRNA expressions of IL-6 and TNF-α in C57BL/6 mouse macrophages treated with 50 μg/mL PM2.5 were 1.15±0.26 and 1.24±0.29 respectively, and 2.75±0.68 and 2.67±0.47 respectively, in those treated with 200 μg/mL PM2.5. The mRNA expressions in CARD9-/- mouse macrophages were significantly lower than those in C57BL/6 mouse macrophages exposed to the same concentration of PM2.5 (all Ps < 0.05).
Conclusion PM2.5 may induce pro-inflammatory cytokines secretion in macrophages though CARD9 gene signaling pathway.
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