title: Mechanical forces-induced human osteoblasts differentiation involves MMP-2/MMP-13/MT1-MMP proteolytic cascade.
abstract: Matrix metalloproteinase (MMP) family proteins play diverse roles in many aspects of cellular processes such as osteoblastic differentiation. Besides, mechanical forces that occur in 3D collagen gel promote the osteoblastic phenotype and accelerate matrix mineralization. Although MMPs have been involved in bone differentiation, the proteolytic cascades triggered by mechanical forces are still not well characterized. In this study, we have investigated the contribution of both proteolytic cascades, MMP-3/MMP-1 and MMP-2/MMP-13/MT1-MMP in the differentiation of human osteoblasts cultured in a floating type I collagen lattice (FL) versus an attached collagen lattice (AL). Compared to AL, contraction of human osteoblasts-populated FL led to a fast (1 day) induction of alkaline phosphatase (ALP), bone sialoprotein (BSP), osteoprotegerin (OPG), and Runx-2 expression. At day 4, osteocalcin (OC) overexpression preceded the formation of calcium-containing nodule formation as assessed by X-ray analyses. MMP-1 and MMP-3 were produced to similar extent by cells cultured in FL and AL, whereas contraction of collagen lattices triggered both mRNA overexpression of MMP-2, MMP-13, and MT1-MMP (i.e., MMP-14), and their activation as evidenced by Western blotting or zymographic analyses. Down-regulating MT1-MMP expression or activity either by siRNA transfection or supplementation of culture medium with TIMP-1 or TIMP-2 highlighted the contribution of that enzyme in OC, ALP, and OPG expression. MMP-2 and MMP-13 were more directly involved in BSP expression. So, these results suggest that the main proteolytic cascade, MMP-2/MMP-13/MT1-MMP, and more particularly, its initial regulator MT1-MMP is involved in osteoblast differentiation through mechanical forces.
authors: Unité INSERM UMRS-926, Interface Biomatériaux/Tissus Hôtes, Institut Biomolécules (IFR53), Faculté d'Odontologie, Université de Reims Champagne-Ardenne, 1 Rue du Maréchal Juin, 51095 Reims Cedex, France.
authors: Stéphane
authors: S
authors: Barthelemi
authors: Julien
authors: J
authors: Robinet
authors: Roselyne
authors: R
authors: Garnotel
authors: Frank
authors: F
authors: Antonicelli
authors: Estelle
authors: E
authors: Schittly
authors: William
authors: W
authors: Hornebeck
authors: Sandrine
authors: S
authors: Lorimier
mesh_terms: D001696:Biomechanical Phenomena; D002454:Cell Differentiation; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D053509:Matrix Metalloproteinase 13 / Q000378:metabolism*; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D010006:Osteoblasts / Q000166:cytology / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D003094:Collagen; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; C522361:MMP2 protein, human; D020778:Matrix Metalloproteinase 2; C507086:MMP14 protein, human; D053511:Matrix Metalloproteinase 14