Activation of the c-Jun is required for NTHi-induced CXCL2 up-regulation. A, Transcription factor ELISAs show that the SLFs activate c-Jun in response to NTHi. B, Phosphorylation assays show that c-Jun of the nuclear fraction is phosphorylated in response to NTHi. C, NTHi-induced CXCL2 up-regulation is noted to be inhibited by Tanshinone IIA in a dose-dependent manner. D, Luciferase assays demonstrate that a dominant-negative inhibition of c-Jun (TAM 67) suppresses NTHi-induced CXCL2 up-regulation. E, ELISA analysis shows that a dominant-negative inhibition of c-Jun (TAM 67) markedly suppresses NTHi-induced CXCL2 up-regulation. ND: not detected. pcDNA: a mock transfection. Results were expressed as fold-induction, taking the value of the non-treated group as 1. The experiments were performed in triplicate and repeated twice. Values are given as the mean ± standard deviation (n = 3). *: p < 0.05.