Effects of JNK1/2 on the inflammation cytokine TNF-α-enhanced production of MMP-3 in human dental pulp fibroblast-like cells.

To investigate the effects of the c-Jun N-terminal kinase (JNK1/2) on the inflammation cytokine tumour necrosis factor-alpha (TNF-α)-enhanced production of matrix metalloproteinase-3 (MMP-3) in human dental pulp fibroblast-like cells (HPFs). HPFs were grown from pulp explants from healthy donors. Primary cultures were established by culturing the cells for 20 to 30 days. The experiments with HPFs were performed between passages 3 and 10. The HPFs were incubated in serum-free medium containing TNF-α for 24 h. The medium in each well was prepared in SDS sample buffer and was analysed for MMP-3 by Western blotting. JNK inhibitor SP601245 markedly inhibited the production of MMP-3 in TNF-α-stimulated human dental pulp fibroblasts. MMP-3 production was enhanced by TNF-α in HPFs; silencing JNK1 and JNK2 expression inhibited this activation. cAMP response element-binding protein (CREB) was activated by TNF-α in HPFs; silencing JNK1 and JNK2 expression inhibited this activation. The activation of CREB via JNK pathways in the presence of TNF-α occurred with enhancement of MMP-3 production in dental pulp fibroblasts.