title: Effect of the release from mechanical stress on osteoclastogenesis in RAW264.7 cells.
abstract: The effects of mechanical stress release on osteoclastogenesis may be as important as those of mechanical stress application. However, the direct effects of mechanical stress on the behavior of osteoclasts has not been thoroughly investigated and there is limited information on the results of the release from mechanical stress. In this study, the effects of mechanical stress application and its release on osteoclast differentiation were examined. The number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated osteoclasts derived from RAW264.7 cells were measured and the expression of osteoclast differentiation genes, which was altered in response to the release from mechanical stress according to the Flexercell tension system was evaluated by real-time PCR. Osteoclast differentiation and fusion were suppressed by mechanical stress application and were rapidly induced after mechanical stress release. The mRNA expression of the osteoclast specific genes, TRAP, matrix metalloproteinase-9 (MMP-9), cathepsin-K (cath-k), calcitonin receptor (CTR), ATPase H+ transporting vacuolar proton pump member I (ATP6i), chloride channel-7 (ClC7) and dendritic cell-specific transmembrane protein (DC-STAMP) was decreased with mechanical stress application, and increased up to 48 h after the release from it. These alterations in gene mRNA expression were associated with the number of osteoclasts and large osteoclasts. Inducible nitric oxide synthetase (iNOS) mRNA was increased with mechanical stress and decreased after its release. Nitric oxide (NO) production was increased with mechanical stress. Nuclear factor of activated T cells cytoplasmic (NFATc) family mRNAs were not altered with mechanical stress, but were up-regulated up to 48 h after the release from it. These findings indicate that the suppression of osteoclast differentiation and fusion induced by mechanical stress is the result of NO increase via iNOS, and that the promotion of osteoclast differentiation and fusion after the release from mechanical stress is related to the NFATc family genes, whose expression remained constant during mechanical stress but was up-regulated after the release from mechanical stress.
authors.affiliation: Department of Orthodontics, Hokkaido University Graduate School of Dental Medicine, Kita-ku, Sapporo 060-8586, Japan.
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Shibata
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Yoshimura
authors.forename: Takashi
authors.initials: T
authors.lastname: Kikuiri
authors.forename: Tomokazu
authors.initials: T
authors.lastname: Hasegawa
authors.forename: Yumi
authors.initials: Y
authors.lastname: Taniguchi
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Deyama
authors.forename: Kuniaki
authors.initials: K
authors.lastname: Suzuki
authors.forename: Junichiro
authors.initials: J
authors.lastname: Iida
mesh_terms: D000135:Acid Phosphatase / Q000235:genetics / Q000502:physiology; D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D056657:Cathepsin K / Q000235:genetics / Q000502:physiology; D002454:Cell Differentiation; D002460:Cell Line; D018118:Chloride Channels / Q000235:genetics / Q000502:physiology; D015870:Gene Expression / Q000235:genetics / Q000502:physiology; D007527:Isoenzymes / Q000235:genetics / Q000502:physiology; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics / Q000502:physiology; D051379:Mice; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000502:physiology; D010010:Osteoclasts / Q000166:cytology / Q000502:physiology*; D011312:Pressure; D018003:Receptors, Calcitonin / Q000235:genetics / Q000502:physiology; D013314:Stress, Mechanical; D000071681:Tartrate-Resistant Acid Phosphatase; D025262:Vacuolar Proton-Translocating ATPases / Q000235:genetics / Q000502:physiology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C097540:CLCN7 protein, human; D018118:Chloride Channels; C501589:DCSTAMP protein, human; D007527:Isoenzymes; D008565:Membrane Proteins; D018003:Receptors, Calcitonin; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase; D056657:Cathepsin K; D020780:Matrix Metalloproteinase 9; D025262:Vacuolar Proton-Translocating ATPases; D019331:NG-Nitroarginine Methyl Ester