title: Adenoviral-mediated transfer of TGF-beta1 but not IGF-1 induces chondrogenic differentiation of human mesenchymal stem cells in pellet cultures.
abstract: OBJECTIVE
  The objective of the present study was to investigate the potential of application of growth factor genes to induce chondrogenic differentiation of human-derived mesenchymal stem cells (MSCs). The growth factor genes evaluated in the present study were transforming growth factor 1 (TGF-beta1) and insulin-like growth factor 1 (IGF-1).
  
  
  METHODS
  Human MSCs were transduced with the adenoviral vectors carrying either TGF-beta1 or IGF-1 (AdTGF-beta1 and AdIGF-1 respectively) or a combination of both growth factor genes at different multiplicities of infection (MOI) and were then made into pellets. Pellets were also made from nontransduced cells and maintained in culture medium supplemented with 10 ng/mL of TGF-beta1. At specified time points, histological analysis, cartilage matrix gene expression, and immunofluorescence were performed to determine the extent of chondrogenic differentiation.
  
  
  RESULTS
  MSCs transduced with the AdTGF-beta1 demonstrated robust chondrogenic differentiation, while those made from AdIGF-1 did not. AdTGF-beta1 pellets demonstrated aggrecan gene expression as early as day 3 of pellet culture, while type II collagen gene expression was detected by day 10 of culture. The AdIGF-1, alone or in combination with TGF-beta1 pellets, did not show any type II collagen gene expression at any time point. By immunofluoresecence, type X collagen was distributed throughout the matrix in TGF-beta1 protein pellets while the growth factor gene pellets displayed scant staining.
  
  
  CONCLUSIONS
  The results suggest that sustained administration of TGF-beta1 may be more effective in suppressing terminal differentiation than intermittent dosing and thus effective for cartilage repair.
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Koichiro
authors.initials: K
authors.lastname: Kawamura
authors.forename: Constance R
authors.initials: CR
authors.lastname: Chu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sobajima
authors.forename: Paul D
authors.initials: PD
authors.lastname: Robbins
authors.forename: Freddie H
authors.initials: FH
authors.lastname: Fu
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Izzo
authors.forename: Christopher
authors.initials: C
authors.lastname: Niyibizi
mesh_terms: D000256:Adenoviridae; D002454:Cell Differentiation / Q000235:genetics*; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000235:genetics*; D024043:Collagen Type II / Q000096:biosynthesis / Q000235:genetics; D024121:Collagen Type X / Q000096:biosynthesis / Q000235:genetics; D005786:Gene Expression Regulation; D018014:Gene Transfer Techniques; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000235:genetics* / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism; D053773:Transforming Growth Factor beta1
chemical_list: D024043:Collagen Type II; D024121:Collagen Type X; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D007334:Insulin-Like Growth Factor I