NFKB1 and infection: We further investigated whether Pug-4 exerted a regulatory role on the NTHi-induced NF-κB activation signaling pathway in A549 cells for two reasons: first, the nuclear factor-kappa B (NF-κB) pathway is essential in inflammatory responses to various pathogen infections, including NTHi (Shuto et al., 2001); second, the translocation of the transcription factor NF-κB from cytosol to the nucleus is critically required for the activation of inflammatory gene transcription.