title: Stretch-induced modulation of matrix metalloproteinases in mineralizing osteoblasts via extracellular signal-regulated kinase-1/2.
abstract: Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) produced by osteoblasts play an essential role in bone remodeling. Hence, these proteins could provide an interesting means by which mechanical loading leads to adaptation of bone. Here, we examined the effect of stretch on MMP-1, -2, -3, -8, -9, -13, and -14, as well as TIMP-1 and -2 gene expression in differentiating, mineralizing, and nonmineralizing human SV-40 immortalized preosteoblast cells. In the mineralizing osteoblast culture, but not in the nonmineralizing cultures, cyclic stretch for only 15 min resulted in an increase of MMP-1 (fourfold) and -3 (depending on differentiation stage up to 25-fold) transcript abundance. No clear effect was observed for other MMPs, TIMP-1 or -2. The increase of MMP-1 and -3 was confirmed on the protein level. Stretching experiments performed in the presence of a specific inhibitor of extracellular signal-regulated kinase (ERK) showed a strong suppression of the stretch-induced increase in MMP-1 and -3. In conclusion, we show that MMP-1 and MMP-3 are mechanosensitive genes in mineralizing the human osteoblast, and that the mechano-induction of these genes is mediated via the ERK pathway. Our findings implicate that these MMPs are important factors in the mechanoregulation of bone turnover. With the ability to generate MMPs at highly stretched sites, osteoblasts can potantially direct osteoclasts to specific bone surface areas prepared for resorption.
authors.affiliation: Department of Orthopaedics, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Justus H
authors.initials: JH
authors.lastname: Jansen
authors.forename: Holger
authors.initials: H
authors.lastname: Jahr
authors.forename: Jan A N
authors.initials: JA
authors.lastname: Verhaar
authors.forename: Huib A P
authors.initials: HA
authors.lastname: Pols
authors.forename: H
authors.initials: H
authors.lastname: Chiba
authors.forename: Harrie
authors.initials: H
authors.lastname: Weinans
authors.forename: Johannes P T M
authors.initials: JP
authors.lastname: van Leeuwen
mesh_terms: D002070:Butadienes; D002113:Calcification, Physiologic / Q000502:physiology*; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D006801:Humans; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000502:physiology*; D009570:Nitriles; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D010766:Phosphorylation; D013718:Tensile Strength; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000378:metabolism
chemical_list: D002070:Butadienes; D009570:Nitriles; D019715:Tissue Inhibitor of Metalloproteinase-1; C113580:U 0126; D019716:Tissue Inhibitor of Metalloproteinase-2; D019950:Mitogen-Activated Protein Kinase 1; D020782:Matrix Metalloproteinases