ABSTRACT
To investigate the kinetics of activation of the activator protein-1(AP-1) and elucidate its role in TNF-? expression induced by lipopolysaccharide(LPS) in rat alveolar macrophages(AM), dynamic changes of the activity of AP-1 were detected with electrophoretic mobility shift assay(EMSA). The phosphorothioate oligodeoxynucleotide (S-ODN) decoy was transfected into AM prior to LPS stimulation. The level of TNF-? in culture supernatants was measured with an ELISA kit. The results showed that after LPS stimulation for 0.5 hour, remarkable activation of AP-1 could be detected and reached the highest level. The activation of AP-1 rapidly decreased at 1 hour, then increased at 3 hours again and reduced at 5 and 8 hours after LPS stimulation. The activation of AP-1 could persist at least 8 hours and showed a dose-dependent manner to LPS within 1000ng/ml. AP-1 S-ODN decoys could markedly inhibit the LPS-induced TNF-? production by rat AM, but it could not completely inhibit the production of TNF-? induced by LPS in rat AM. It is suggested that LPS could induce activation of AP-1 in rat AM; AP-1 played an important role in LPS-induced inflammatory response. It is also suggested that AP-1 involved in the regulation on LPS-induced TNF-? production by rat AM, however, entirely inhibition of the activity of AP-1 could not completely prevent TNF-? production by rat AM. It is also implied that other nuclear factors might also play an important role in the regulation on LPS-induced TNF-? expression by rat AM.
