Role of JNK signaling pathway in hyperoxia-induced expression of connective tissue growth factor in A549 cells

Abstract

Objective To investigate the role of c-Jun N-terminal kinase(JNK)signaling pathway in hyperoxia-induced expression of connective tissue growth factor(CTGF)in A549 cells. Methods The cultured A549 cells were seeded in 6-well culture plates at a density of 1×105 cells/ml(0.5 ml/well, 24 wells in total)and were randomly divided into 4 groups(n=6 each)using a random number table: control group(group C); 95% oxygen group(group 95% O2); room air plus SP600125(JNK inhibitor)group(group C+ SP); 95% oxygen plus SP600125 group(group 95% O2+ SP). SP600125 5 μmol/L was added to each well in C+ SP and 95% O2+ SP groups.The A549 cells were incubated for 48 h in an incubator filled with room air(C and C+ SP groups)or 95% oxygen(95% O2 and 95% O2+ SP groups). The expression of phosphorylated JNK(p-JNK)and CTGF mRNA was determined using Western blot and real-time reverse transcriptase polymerase chain reaction, respectively. Results Compared with group C, no significant change was found in the expression of p-JNK and CTGF mRNA in group C+ SP(P>0.05), and the expression of p-JNK and CTGF mRNA was significantly up-regulated in group 95% O2(P<0.05). Compared with group 95% O2, the expression of p-JNK and CTGF mRNA was significantly down-regulated in group 95% O2+ SP(P<0.05). Conclusion JNK signaling pathway activation is involved in up-regulation of hyperoxia-induced CTGF mRNA expression in A549 cells. Key words: Oxygen; Epithelial cell; Pulmonary alveoli; JNK mitogen-activated protein kinases; Connective tissue growth factor