Research Paper Volume 13, Issue 15 pp 19442—19459

CC16-TNF-α negative feedback loop formed between Clara cells and normal airway epithelial cells protects against diesel exhaust particles exposure-induced inflammation

CC16 secretion from CC16+ cells protects against DEP-induced bronchial epithelial cell inflammation via activation of autophagy. CC16+ cell conditioned medium containing different concentrations of CC16 is prepared, and used to culture BEAS-2B cells. The CC16 level in the medium of Ctrl, DEP, DEP+ CC16+, DEP+ DEP-CC16+ group is 0, 0, 144.7 and 46.5 ng/ml, respectively. After 12 h of culture, the cells and culture supernatants are collected. (A) LC3B and p62 protein expression in BEAS-2B cells are detected by western blot. (B) Autophagy induction is evaluated by LC3B immunostaining (× 400). Autophagosomes are identified as bright green dots. (C–E) TNF-α, IL-6, and IL-8 level in culture supernatants are detected by ELISA. ***P #P ##P , and ###P  vs. DEP group; and &P &&P , and &&&P  vs. DEP+ CC16+ group.

Figure 6. CC16 secretion from CC16+ cells protects against DEP-induced bronchial epithelial cell inflammation via activation of autophagy. CC16+ cell conditioned medium containing different concentrations of CC16 is prepared, and used to culture BEAS-2B cells. The CC16 level in the medium of Ctrl, DEP, DEP+ CC16+, DEP+ DEP-CC16+ group is 0, 0, 144.7 and 46.5 ng/ml, respectively. After 12 h of culture, the cells and culture supernatants are collected. (A) LC3B and p62 protein expression in BEAS-2B cells are detected by western blot. (B) Autophagy induction is evaluated by LC3B immunostaining (× 400). Autophagosomes are identified as bright green dots. (CE) TNF-α, IL-6, and IL-8 level in culture supernatants are detected by ELISA. ***P < 0.001 vs. ctrl; #P < 0.05, ##P < 0.01, and ###P < 0.001 vs. DEP group; and &P < 0.05, &&P < 0.01, and &&&P < 0.001 vs. DEP+ CC16+ group.