title: Effect of compressive force on the expression of MMPs, PAs, and their inhibitors in osteoblastic Saos-2 cells.
abstract: Bone matrix turnover is regulated by matrix metalloproteinases (MMPs), tissue inhibitors of matrix metalloproteinases (TIMPs), and the plasminogen activation system, including tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), and plasminogen activator inhibitor type-1 (PAI-1). We previously demonstrated that 1.0g/cm(2) of compressive force was an optimal condition for inducing bone formation by osteoblastic Saos-2 cells. Here, we examined the effect of mechanical stress on the expression of MMPs, TIMPs, tPA, uPA, and PAI-1 in Saos-2 cells. The cells were cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum and with or without continuously compressive force (0.5-3.0g/cm(2)) for up to 24h. The levels of MMPs, TIMPs, uPA, tPA, and PAI-1 gene expression were estimated by determining the mRNA levels using real-time PCR, and the protein levels were determined using ELISA. The expression levels of MMP-1, MMP-2, MMP-14, and TIMP-1 markedly exceeded the control levels at 1.0g/cm(2) of compressive force, whereas the expression levels of MMP-3, MMP-13, TIMP-2, TIMP-3, TIMP-4, tPA, uPA, and PAI-1 markedly exceeded the control levels at 3.0g/cm(2). These results suggest that mechanical stress stimulates bone matrix turnover by increasing these proteinases and inhibitors, and that the mechanism for the proteolytic degradation of bone matrix proteins differs with the strength of the mechanical stress.
authors.affiliation: Department of Orthodontics, Nihon University School of Dentistry, 1-8-13 Kanda, Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
authors.forename: Narihiro
authors.initials: N
authors.lastname: Mitsui
authors.forename: Naoto
authors.initials: N
authors.lastname: Suzuki
authors.forename: Yuki
authors.initials: Y
authors.lastname: Koyama
authors.forename: Momoko
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: Kichibee
authors.initials: K
authors.lastname: Otsuka
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Shimizu
authors.forename: Masao
authors.initials: M
authors.lastname: Maeno
mesh_terms: D045744:Cell Line, Tumor; D019245:Compressive Strength; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000096:biosynthesis / Q000235:genetics; D010006:Osteoblasts / Q000201:enzymology / Q000378:metabolism; D010960:Plasminogen Activators / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013314:Stress, Mechanical; D019714:Tissue Inhibitor of Metalloproteinases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D019714:Tissue Inhibitor of Metalloproteinases; D010960:Plasminogen Activators; D020782:Matrix Metalloproteinases