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Lipopolysaccharide‐regulated production of bone sialoprotein and interleukin‐8 in human periodontal ligament fibroblasts: the role of toll‐like receptors 2 and 4 and the MAPK pathway
Author(s) -
Zhang Y.,
Li X.
Publication year - 2015
Publication title -
journal of periodontal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.31
H-Index - 83
eISSN - 1600-0765
pISSN - 0022-3484
DOI - 10.1111/jre.12193
Subject(s) - bone sialoprotein , porphyromonas gingivalis , periodontal fiber , bone resorption , chemistry , osteoclast , cementoblast , proinflammatory cytokine , microbiology and biotechnology , periodontitis , immunology , receptor , osteocalcin , medicine , biology , inflammation , dentistry , cementum , alkaline phosphatase , biochemistry , enzyme , dentin
Background and Objective Lipopolysaccharide ( LPS ) on the cell wall of periodontal pathogens is a major mediator of the inflammatory response and can enhance alveolar bone resorption in periodontitis. Bone sialoprotein is an early marker of osteoblast differentiation. The proinflammatory cytokine, interleukin‐8 ( IL ‐8), induces osteoclast differentiation, maturation and maintenance of bone resorption activity. However, the effects of LPS from periodontal pathogens on the expression of bone sialoprotein and IL ‐8 in human osteoblasts and the mechanism of periodontal bone metabolism regulation are rather unclear. The objectives of this study were to determine the effects of Porphyromonas gingivalis LPS on the production of bone sialoprotein and IL‐8 in human periodontal ligament fibroblasts ( hPDLF s), and to investigate whether toll‐like receptor ( TLR ) 2, TLR 4 and MAPK s pathways are involved in the regulation of production of bone sialoprotein and IL‐8 by P. gingivalis LPS . Material and Methods The third‐generation of h PDLF s were cultured with mineralization‐inducing culture medium. After h PDLF s were treated with P . gingivalis LPS , bone sialoprotein and IL ‐8 m RNA expression were detected using Real time PCR . Then h PDLF s were transiently transfected with si TLR 2 or si TLR 4 (20 n m ) or inhibited by MAPK signaling pathways inhibitors, and then bone sialoprotein and IL ‐8 m RNA and protein expression were also detected using Real time PCR and western blotting. Results Treatments with 0.01 and 0.1 mg/L of P. gingivalis LPS for 8 h up‐regulated bone sialoprotein mRNA expression, whereas 10 and 100 mg/L of P. gingivalis LPS induced a significant decrease in the expression of bone sialoprotein mRNA . In contrast, IL 8 mRNA levels were increased significantly by 10 mg/L of P. gingivalis LPS . Interestingly, small interfering RNA (siRNA) knock down of the TLR 2 and ERK 1/2 inhibitor, PD98059, abolished the effects of P. gingivalis LPS on the bone sialoprotein mRNA level, whereas si RNA knock down of the TLR 2 and p38 MAPK inhibitor, SB 203580, blocked the effect of P. gingivalis LPS on IL ‐8 in hPDLF s. Conclusion This study suggests that in hPDLF s, P. gingivalis LPS suppresses bone sialoprotein and enhances IL‐8 gene and protein expression via TLR 2 and ERK 1/2 or the p38 MAPK signaling pathway, respectively.