title: Early BMP, Wnt and Ca(2+)/PKC pathway activation predicts the bone forming capacity of periosteal cells in combination with calcium phosphates.
abstract: The development of osteoinductive calcium phosphate- (CaP) based biomaterials has, and continues to be, a major focus in the field of bone tissue engineering. However, limited insight into the spatiotemporal activation of signalling pathways has hampered the optimisation of in vivo bone formation and subsequent clinical translation. To gain further knowledge regarding the early molecular events governing bone tissue formation, we combined human periosteum derived progenitor cells with three types of clinically used CaP-scaffolds, to obtain constructs with a distinct range of bone forming capacity in vivo. Protein phosphorylation together with gene expression for key ligands and target genes were investigated 24 hours after cell seeding in vitro, and 3 and 12 days post ectopic implantation in nude mice. A computational modelling approach was used to deduce critical factors for bone formation 8 weeks post implantation. The combined Ca(2+)-mediated activation of BMP-, Wnt- and PKC signalling pathways 3 days post implantation were able to discriminate the bone forming from the non-bone forming constructs. Subsequently, a mathematical model able to predict in vivo bone formation with 96% accuracy was developed. This study illustrates the importance of defining and understanding CaP-activated signalling pathways that are required and sufficient for in vivo bone formation. Furthermore, we demonstrate the reliability of mathematical modelling as a tool to analyse and deduce key factors within an empirical data set and highlight its relevance to the translation of regenerative medicine strategies.
authors.affiliation: Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium.
authors.forename: Johanna
authors.initials: J
authors.lastname: Bolander
authors.affiliation: Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium.
authors.forename: Yoke Chin
authors.initials: YC
authors.lastname: Chai
authors.affiliation: Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Biomechanics Research Unit, University of Liege, Chemin des Chevreuils 1, BAT 52/3, 4000 Liege 1, Belgium; Biomechanics Section, KU Leuven, Celestijnenlaan 300C, Bus 2419, 3001 Leuven, Belgium.
authors.forename: Liesbet
authors.initials: L
authors.lastname: Geris
authors.affiliation: Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Department of Materials Engineering, KU Leuven, Kasteelpark Arenberg 44, Bus 2450, 3001 Heverlee, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Schrooten
authors.affiliation: Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium.
authors.forename: Dennis
authors.initials: D
authors.lastname: Lambrechts
authors.affiliation: Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, The Royal National Orthopaedic Hospital, Stanmore, Middlesex, HA7 4LP, United Kingdom.
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Roberts
authors.affiliation: Tissue Engineering Laboratory, Skeletal Biology and Engineering Research Center, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium; Prometheus, Division of Skeletal Tissue Engineering, KU Leuven, O&N 1, Herestraat 49, Bus 813, 3000 Leuven, Belgium. Electronic address: frank.luyten@uzleuven.be.
authors.forename: Frank P
authors.initials: FP
authors.lastname: Luyten
mesh_terms: D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002130:Calcium Phosphates / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D002478:Cells, Cultured; D006801:Humans; D008819:Mice, Nude; D010012:Osteogenesis / Q000187:drug effects; D010521:Periosteum / Q000166:cytology; D011493:Protein Kinase C / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*; D060449:Wnt Signaling Pathway / Q000187:drug effects
chemical_list: D001672:Biocompatible Materials; D002130:Calcium Phosphates; D011493:Protein Kinase C; D002118:Calcium
keywords: Bone tissue engineering; Calcium phosphate; Cell signalling; Modelling; Osteogenesis; Progenitor cell