Periodontal ligament cells under intermittent tensile stress regulate mRNA expression of osteoprotegerin and tissue inhibitor of matrix metalloprotease-1 and -2.
We studied the mRNA expression of osteoprotegerin (OPG), receptor activator of NF-kappa B ligand (RANKL), tissue inhibitor of matrix metalloprotease (TIMP)-1 and -2, and matrix metalloprotease (MMP)-1 and -2 by human periodontal ligament (PDL) cells under intermittent tensile stress using a Flexercell Strain Unit. Analysis by reverse transcriptase-polymerase chain reaction showed that mechanical force upregulated OPG mRNA. We also demonstrated that the protein concentration of OPG in conditioned medium increased upon loading with tensile stress, as determined by enzyme-linked immunosorbent assay. TIMP-1 and -2 mRNA levels also increased, whereas levels of RANKL, MMP-1, and MMP-2 mRNA were barely affected. We further examined the effect of loading with tensile stress and addition of Salmonella abortus equi lipopolysaccharide (LPS) on the mRNA expression of PDL cells. The amount of OPG mRNA induced by mechanical strain was found to decrease with the addition of LPS to cultures. The induction of OPG mRNA expression by stretching was inhibited in the presence of indomethacin or genistein, whereas TIMP-1 mRNA expression induced by stretching was inhibited by the addition of cycloheximide, suggesting that tensile stress regulates cyclooxygenase activities, tyrosine phosphorylation, and de novo protein synthesis in PDL cells through the induction of OPG and TIMP-1 mRNA expression. These results provide evidence that the mechanical stimulus of stretching is responsible for the observed regulation of bone resorption and tissue degradation in PDL tissue.
Biochemistry and Molecular Biology, Department of Oral Health Science, Graduate School of Dental Medicine, Hokkaido University, North 13, West 7, Kita-ku, 060-8586, Sapporo, Japan.
Kiyomi
K
Tsuji
Keiji
K
Uno
Gui Xia
GX
Zhang
Masato
M
Tamura
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry; D003513:Cycloheximide / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008070:Lipopolysaccharides / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D053244:Osteoprotegerin; D010513:Periodontal Ligament / Q000166:cytology* / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000378:metabolism; D053245:RANK Ligand; D012333:RNA, Messenger / Q000378:metabolism*; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear / Q000235:genetics / Q000378:metabolism*; D018124:Receptors, Tumor Necrosis Factor; D013314:Stress, Mechanical; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000235:genetics / Q000378:metabolism*; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000235:genetics / Q000378:metabolism*
D002352:Carrier Proteins; D003470:Culture Media; D004791:Enzyme Inhibitors; D006023:Glycoproteins; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D053244:Osteoprotegerin; D011500:Protein Synthesis Inhibitors; D053245:RANK Ligand; D012333:RNA, Messenger; D053246:Receptor Activator of Nuclear Factor-kappa B; D018160:Receptors, Cytoplasmic and Nuclear; D018124:Receptors, Tumor Necrosis Factor; C505686:TNFRSF11A protein, human; C506030:TNFRSF11B protein, human; C505688:TNFSF11 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D003513:Cycloheximide