Activator Protein‐1 Is the Preferred Transcription Factor for Cooperative Interaction with Nuclear Factor‐kB in Respiratory Syncytial Virus‐Induced Interleukin‐8 Gene Expression in Airway Epithelium

The role of "oxidant-sensitive" transcription factors activator protein (AP)-1, nuclear factor (NF)-kappaB, and NF-IL6 in respiratory syncytial virus (RSV)-induced interleukin (IL)-8 gene expression in A549 epithelial cells was evaluated. RSV infection resulted in increased binding of each of these transcription factors. Transfection of A549 cells with plasmids containing serial truncations of the 5'-flanking region of the IL-8 gene revealed a positive cooperative effect of the binding sites for AP-1 and NF-kappaB. Mutation of either region markedly diminished responsiveness of the promoter to RSV. Mutation of the NF-IL6 site had minimal effect in the presence of intact binding sites for NF-kappaB and AP-1. The antioxidants NAC (N-acetylcysteine), DMSO, and DMPO (5,5-dimethyl-1-pyrroline N-oxide) did not inhibit RSV-induced binding of NF-kappaB; however, binding of AP-1 and NF-IL6 was inhibited. These observations suggest that AP-1 may be the preferred transcription factor (over NF-IL6) for cooperative interaction with NF-kappaB in RSV-induced IL-8 production.