Fig. 3. IL-17A/TNFα-mediated synergistic induction of IL-19 and IL-20 is regulated by a p38 MAPK-, NF-κB-, and JNK1/2-dependent mechanism. (A~D) Human keratinocytes were preincubated with the indicated inhibitors for 45 minutes before being stimulated with IL-17A (100 ng/ml), TNFα (10 ng/ml), or IL-17A combined with TNFα for 24 hours. (E~H) Human keratinocytes were transfected with specific siRNA as indicated. A non-targeting pool of siRNAs served as negative control (siCon). (A, B, E, G) IL-19 and IL-20 mRNA expression were measured by qPCR (n=4). RPLP0 was used for normalisation. (C, D, F, H) IL-19 and IL-20 protein levels were measured by ELISA (n=4). IL: interleukin, TNFα: tumour necrosis factor alpha. ^*Non-inhibited cells compared with inhibited cells; transfected cells against (sip38αβ), p65 (sip65), JNK1/2 (siJNK1/2) compared with control siRNA (siCon) (p<0.05).