Interleukin-13 Inhibits Lipopolysaccharide-Induced BPIFA1 Expression in Nasal Epithelial Cells
Fig 3
JNK/c-Jun pathway is involved in LPS-mediated up-regulation of BPIFA1 expression in nasal epithelial cells.
(A) Cells were pretreated for 1 h with 20 μM PD98059 (ERK inhibitor), 10 μM SP600125 (JNK inhibitor), or 20 μM SB203580 (p38 inhibitor) and incubated with 10 μg/ml LPS for 2 h. (B) Cells were transfected with a JNK-dominant negative (DN-JNK) mutant for 24 h or pretreated with SP600125 for 30 min prior to incubation with LPS for 1 h. The protein expression levels were determined using western blot. β-actin was used as the loading control. The western blots were carried out independently in triplicate and results were representative of one of three independent experiments. The expression level of each protein was quantified by signal intensity and was indicated at the bottom of each lane. The quantitative analysis of western blot for three independent experiments was shown in S2 Fig. ANOVA with Tukey’s test was used to compare the overall difference between the groups. P < 0.05 was considered statistically significant.