title: The effect of unlocking RGD-motifs in collagen I on pre-osteoblast adhesion and differentiation.
abstract: Denaturation of extracellular matrix proteins exposes cryptic binding sites. It is hypothesized that binding of cell adhesion receptors to these cryptic binding sites regulates cellular behaviour during tissue repair and regeneration. To test this hypothesis, we quantify the adhesion of pre-osteoblastic cells to native (Col) and partially-denatured (pdCol) collagen I using single-cell force spectroscopy. During early stages of cell attachment (< or =180 s) pre-osteoblasts (MC3T3-E1) adhered significantly stronger to pdCol compared to Col. RGD (Arg-Gly-Asp)-containing peptides suppressed this elevated cell adhesion. We show that the RGD-binding alpha(5)beta(1)- and alpha(v)-integrins mediated pre-osteoblast adhesion to pdCol, but not to Col. On pdCol pre-osteoblasts had a higher focal adhesion kinase tyrosine-phosphorylation level that correlated with enhanced spreading and motility. Moreover, pre-osteoblasts cultured on pdCol showed a pronounced matrix mineralization activity. Our data suggest that partially-denatured collagen exposes RGD-motifs that trigger binding of alpha(5)beta(1)- and alpha(v)-integrins. These integrins initiate cellular processes that stimulate osteoblast adhesion, spreading, motility and differentiation. Taken together, these quantitative insights reveal an approach for the development of alternative collagen I- based surfaces for tissue engineering applications.
authors.affiliation: Cellular Machines, Biotechnology Center, University of Technology Dresden, Am Tatzberg 47-49, 01307 Dresden, Germany.
authors.forename: Anna V
authors.initials: AV
authors.lastname: Taubenberger
authors.forename: Maria A
authors.initials: MA
authors.lastname: Woodruff
authors.forename: Huifen
authors.initials: H
authors.lastname: Bai
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Muller
authors.forename: Dietmar W
authors.initials: DW
authors.lastname: Hutmacher
mesh_terms: D000273:Adipose Tissue / Q000166:cytology; D020816:Amino Acid Motifs; D000818:Animals; D001696:Biomechanical Phenomena / Q000187:drug effects; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048430:Cell Shape / Q000187:drug effects; D024042:Collagen Type I / Q000737:chemistry* / Q000648:ultrastructure; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D051417:Focal Adhesion Kinase 1 / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D051379:Mice; D018625:Microscopy, Atomic Force; D009842:Oligopeptides / Q000494:pharmacology*; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology / Q000648:ultrastructure; D010012:Osteogenesis / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D011489:Protein Denaturation / Q000187:drug effects; D013234:Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism
chemical_list: D024042:Collagen Type I; D016023:Integrins; D009842:Oligopeptides; C047981:arginyl-glycyl-aspartic acid; D051417:Focal Adhesion Kinase 1