PMA synergistically enhances up-regulation of MUC5AC induced by activation of TLR signaling.

<p>(<b>A</b>) PMA synergistically enhanced MUC5AC expression induced only by NTHi, <i>S.p.</i> and PGN, but not by TNF-α and IL-6, as assessed by MUC5AC-dependent promoter Luciferase assay. Values are the means ± S.D. (n = 3). <i>*p<0.05</i> vs. NTHi, <i>S.p.</i>, or PGN alone; <i>^#p>0.05</i> vs. TNF-α or IL-6 alone. (<b>B</b>) PMA synergized with either NTHi or <i>S.p.</i>, but not with TNF-α to enhance MUC5AC expression in a dose-dependent manner. Values are the means ± S.D. (n = 3). <i>*p<0.05</i> vs. PMA alone; <i>^#p>0.05</i> vs. PMA alone. (<b>C</b>) PGN-induced MUC5AC transcription was synergistically enhanced by PMA in HEK293-TLR2 cells, but not in HEK293-pcDNA cells. Values are the means ± S.D. (n = 3). <i>*p<0.05</i> vs. PGN alone. (<b>D</b>) Synergistic enhancement of MUC5AC expression by PMA was also observed in the cells treated with TLR ligands, such as PGN, Zymosan, Poly(I:C) and LPS, respectively. Values are the means ± S.D. (n = 3). <i>*p<0.05</i> vs. PGN, Zymosan, Poly(I:C), or LPS alone. The data shown are representative of three independent experiments. −, absence of; +, presence of; <i>S.p.</i>, <i>Streptococcus pneumoniae</i>; NTHi, nontypeable <i>Haemophilus influenzae</i>.