title: Osteogenic lineage restriction by osteoprogenitors cultured on nanometric grooved surfaces: the role of focal adhesion maturation.
abstract: The differentiation of progenitor cells is dependent on more than biochemical signalling. Topographical cues in natural bone extracellular matrix guide cellular differentiation through the formation of focal adhesions, contact guidance, cytoskeletal rearrangement and ultimately gene expression. Osteoarthritis and a number of bone disorders present as growing challenges for our society. Hence, there is a need for next generation implantable devices to substitute for, or guide, bone repair in vivo. Cellular responses to nanometric topographical cues need to be better understood in vitro in order to ensure the effective and efficient integration and performance of these orthopedic devices. In this study, the FDA-approved plastic polycaprolactone was embossed with nanometric grooves and the response of primary and immortalized osteoprogenitor cells observed. Nanometric groove dimensions were 240 nm or 540 nm deep and 12.5 μm wide. Cells cultured on test surfaces followed contact guidance along the length of groove edges, elongated along their major axis and showed nuclear distortion; they formed more focal complexes and lower proportions of mature adhesions relative to planar controls. Down-regulation of the osteoblast marker genes RUNX2 and BMPR2 in primary and immortalized cells was observed on grooved substrates. Down-regulation appeared to directly correlate with focal adhesion maturation, indicating the involvement of ERK 1/2 negative feedback pathways following integrin-mediated FAK activation.
authors.affiliation: Centre for Cell Engineering, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK. Electronic address: 0909057c@student.gla.ac.uk.
authors.forename: John W
authors.initials: JW
authors.lastname: Cassidy
authors.affiliation: Centre for Cell Engineering, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Jemma N
authors.initials: JN
authors.lastname: Roberts
authors.affiliation: Centre for Cell Engineering, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Carol-Anne
authors.initials: CA
authors.lastname: Smith
authors.affiliation: Kelvin Nanotechnology, James Watt Nanofabrication Centre, University of Glasgow, Glasgow G12 8LT, UK.
authors.forename: Mary
authors.initials: M
authors.lastname: Robertson
authors.affiliation: Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: Kate
authors.initials: K
authors.lastname: White
authors.affiliation: Network of Excellence for Functional Biomaterials (NFB), National University of Ireland, Galway, Ireland.
authors.forename: Manus J
authors.initials: MJ
authors.lastname: Biggs
authors.affiliation: Bone & Joint Research Group, Centre for Human Development, Stem Cells and Regeneration, Institute of Developmental Sciences, University of Southampton, Southampton SO16 6YD, UK.
authors.forename: Richard O C
authors.initials: RO
authors.lastname: Oreffo
authors.affiliation: Centre for Cell Engineering, Institute of Biomedical and Life Sciences, Joseph Black Building, University of Glasgow, Glasgow G12 8QQ, UK.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Dalby
mesh_terms: D052006:Bone Morphogenetic Protein Receptors, Type II / Q000235:genetics / Q000378:metabolism; D019070:Cell Lineage / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D022001:Focal Adhesions / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D049329:Nanostructures / Q000737:chemistry*; D010012:Osteogenesis / Q000187:drug effects*; D011091:Polyesters / Q000737:chemistry* / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology*; D013499:Surface Properties
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D011091:Polyesters; C493709:RUNX2 protein, human; C016240:polycaprolactone; C498218:BMPR2 protein, human; D052006:Bone Morphogenetic Protein Receptors, Type II
keywords: Bone formation; Contact guidance; Focal adhesion; Tissue engineering; Topography