title: Osteogenesis by human mesenchymal stem cells cultured on silk biomaterials: comparison of adenovirus mediated gene transfer and protein delivery of BMP-2.
abstract: Bone tissue engineering, gene therapy based on human mesenchymal stem cells (MSCs) and silk fibroin biomaterials were combined to study the impact of viral transfection on MSC osteogenic performance in vitro. MSCs were transduced with adenovirus containing a human BMP-2 (Ad-BMP-2) gene at clinically reasonable viral concentrations and cultured for 4 weeks. Controls with nontransfected MSCs, but exposed to exogenous BMP-2 concentrations on an analogous time profile as that secreted by the Ad-BMP-2 group, were compared. Both the Ad-BMP-2 MSC group and the exogenous protein BMP-2 group strongly expressed osteopontin and bone sialoprotein. Cells secreted a matrix that underwent mineralization on the silk fibroin scaffolds, forming clusters of osseous material, as determined by micro-computed tomography. The expression of osteogenic marker proteins and alkaline phosphatase was significantly higher in the Ad-BMP-2 MSC group than in the exogenous protein BMP-2 group, and no significant differences in mineralization were observed in two of the three MSC sources tested. The results demonstrate that transfection resulted in higher levels of expression of osteogenic marker genes, no change in proliferation rate and did not impact the capacity of the cells to calcify tissues on these protein scaffolds. These findings suggest additional options to control differentiation where exogenous additions of growth factors or morphogens can be replaced with transfected MSCs.
authors.affiliation: Department of Chemistry and Applied Biosciences, ETH Zuerich, Wolfgang-Pauli Str. 10, 8093 Zuerich, Switzerland.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Meinel
authors.forename: Sandra
authors.initials: S
authors.lastname: Hofmann
authors.forename: Oliver
authors.initials: O
authors.lastname: Betz
authors.forename: Robert
authors.initials: R
authors.lastname: Fajardo
authors.forename: Hans P
authors.initials: HP
authors.lastname: Merkle
authors.forename: Robert
authors.initials: R
authors.lastname: Langer
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Evans
authors.forename: Gordana
authors.initials: G
authors.lastname: Vunjak-Novakovic
authors.forename: David L
authors.initials: DL
authors.lastname: Kaplan
mesh_terms: D000256:Adenoviridae / Q000235:genetics*; D000469:Alkaline Phosphatase / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D005349:Fibroins / Q000494:pharmacology; D005822:Genetic Vectors / Q000235:genetics; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D058574:Integrin-Binding Sialoprotein; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012795:Sialoglycoproteins / Q000378:metabolism; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods; D014162:Transfection; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000494:pharmacology / Q000502:physiology*
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D006023:Glycoproteins; C546871:IBSP protein, human; D058574:Integrin-Binding Sialoprotein; D012795:Sialoglycoproteins; D016212:Transforming Growth Factor beta; C024229:osteopoietin; D005349:Fibroins; D000469:Alkaline Phosphatase; D002118:Calcium