Fig. 7.
p38α deficiency up-regulates IL-27 expression by enhancing JNK–c-Jun axis in DCs. (A–G) Bone marrow cells were isolated from wild-type (WT) and p38αCreER mice to culture BMDCs. BMDCs were stimulated with LPS to examine the activities of JNK, ERK, and p38 (A). BMDCs were pretreated with JNK inhibitor SP600125, ERK inhibitor U0126, or vehicle and then stimulated with LPS for 5 h to analyze Il27p28 expression (n = 5; B). BMDCs were stimulated with LPS to examine the activities of MKK4 and MKK7 (C) and the activities of TAK1, MLK3, and c-Jun (D). BMDCs were pretreated with AP-1 inhibitor SR 11302 or vehicle and then stimulated with LPS for 60 min to analyze the activities of JNK and c-Jun (E) or for 5 h to check Il27p28 expression (n = 5; F). ChIP assays were performed with LPS-pretreated BMDCs, and the abundance of c-Jun bound to the AP-1 binding site on Il27p28 promoter was determined (n = 3; G). (H) p28 luciferase reporter (−852 or −313–455) or pGL3-basic vector was cotransfected with Renilla and c-Jun expression plasmid or empty vector (control) into DC2.4 cells to examine luciferase activities (n = 3). The numbers below the lanes indicate the band intensity relative to that of the loading control GAPDH. Data represent mean ± SEM. Two-way ANOVA with Bonferroni posttest (B, F, and H). Results were replicated (n = 3 experiments). *P < 0.05; **P < 0.01; ***P < 0.001; ns, not significant.