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


Figure 2. DEP exposure induces C/EBPα hypermethylation and decreases CC16 production and secretion in CC16+ Cells. CC16+ cells are exposed to 5 ppm SRM 1650b (the commercial DEP matter) in the presence of DAC or not for 48 h, and then cells and culture supernatants are collected. (A) MSP analysis is performed to detect the methylation of C/EBPα promoter. Lane U, amplified product with primers recognizing unmethylated C/EBPα sequence. Lane M, amplified product with primers recognizing methylated C/EBPα sequence. (B, C) The mRNA and protein expression of C/EBPα are determined by RT-PCR and western blot assay. (D, E) CC16 mRNA expression and level in culture supernatants are detected by RT-PCR and ELISA assay. (FH) After treatment of CC16+ cells with different concentrations of SRM 1650b (0.1, 1, 3, 5 and 10 ppM), C/EBPα and CC16 mRNA expression, C/EBPα protein expression, and CC16 level in culture supernatants are determined by RT-PCR, western blot and ELISA assay. **P < 0.01 and ***P < 0.001 vs. Ctrl group; ##P < 0.01 and ###P < 0.001 vs. DEP group.