up-regulation of tlr2 and tlr4 in high mobility group box1-stimulated macrophages in pulpitis patients

objective(s): high mobility group box1 (hmgb1) is a nonhistone, dna-binding protein that serves a crucial role in regulating gene transcription and is involved in a variety of proinflammatory, extracellular activities. the aim of this study was to explore whether hmgb1 stimulation can up-regulate the expression of toll-like receptor 2 (tlr2) and toll-like receptor 4 (tlr4) on macrophages from pulpitis and to clarify the subsequent events involving th17 cells and th17 cell-associated cytokine changes. materials and methods: having prepared dental pulp tissues of pulpitis and healthy controls, macrophage were isolated and cultured. macrophages were thereafter stimulated by hmgb1 time course. rt-qpcr, flowcytometer, immunofluorescence, western blotting, and elisa techniques were used in the present research. results: our results showed that the expression of tlr2 and tlr4 on macrophages stimulated with hmgb1 increased in pulpitis compared with controls (macrophages without hmgb1 stimulation) with a statistical significance (p<0.001). in addition, the levels of il-17, il-23, and il-6 in supernatants from cultured macrophages stimulated with hmgb1 from pulpitis increased, and nf-kb, the downstream target of tlr2 and tlr4, also showed a marked elevation after macrophages’ stimulation by hmgb1. conclusion: the evidence from the present study suggests that the enhanced tlr2 and tlr4 pathways and th17 cell polarization may be due to hmgb1 stimulation in pulpitis.