Activation of NF-kappa B mediates ICAM-1 induction in respiratory cells exposed to an adenovirus-derived vector

Gene transfer to the respiratory tract by replication-deficient adenoviruse s is limited by the induction of inflammatory and immune responses. We prev iously demonstrated that a E1-E3-deleted recombinant adenovirus carrying th e expression cassette for the cystic fibrosis gene (Ad.CFTR) upregulates th e expression of the pro-inflammatory intercellular adhesion molecule-1 (ICA M-1) both in vitro and in vivo. In the present work we suggest a role for t he nuclear factor-kB (NF-kB) in Ad.CFTR-dependent up-regulation of ICAM-1 i n respiratory epithelial A549 cells. Specifically, Ad.CFTR induced transloc ation of NF-kB into the nucleus and binding to the proximal -228/-218 NF-kB consensus sequence on the ICAM-1 promoter. Ad.CFTR also stimulated a 13-fo ld increase in NF-kB-dependent expression of the CAT reporter gene under th e control of a region of the ICAM-1 promoter, including the proximal NF-kB consensus sequence. The Ad.CFTR-dependent increase of ICAM-1 mRNA was aboli shed by inhibitors of NF-kB, such as N-acetyl-L-cysteine, pyrrolidine dithi ocarbamate, parthenolide and the synthetic peptide SN50. All these inhibito rs abolished both Ad.CFTR-induced NF-kB DNA binding and transactivating act ivities. These results indicate a critical role of NF-kB in the pro-inflamm atory response elicited by replication-deficient adenoviral vectors in resp iratory cells.