title: Non-viral delivery of inductive and suppressive genes to adipose-derived stem cells for osteogenic differentiation.
abstract: OBJECTIVE
  To assess the effects of co-delivering osteoinductive DNA and/or small interfering RNA in directing the osteogenic differentiation of human adipose-derived stem cells (hADSCs) using a combinatorial, non-viral gene delivery approach.
  
  
  METHODS
  hADSCs were transfected using combinations of the following genes: BMP2, siGNAS and siNoggin using poly(β-amino esters) or lipid-like molecules. A total of 15 groups were evaluated by varying DNA doses, timing of treatment, and combinations of signals. All groups were cultured in osteogenic medium for up to 37 days, and outcomes were measured using gene expression, biochemical assays, and histology.
  
  
  RESULTS
  Biomaterials-mediated gene delivery led to a dose-dependent up-regulation of BMP2 and significant gene silencing of GNAS and Noggin in hADSCs. BMP2 alone slightly up-regulates osteogenic marker expression in hADSCs. In contrast, co-delivery of BMP2 and siGNAS or siNoggin significantly accelerates the hADSC differentiation towards osteogenic differentiation, with marked increase in bone marker expression and mineralization.
  
  
  CONCLUSIONS
  We report a combinatorial platform for identifying synergistic interactions among multiple genetic signals associated with osteogenic differentiation of hADSCs. Our results suggest that inductive or suppressive genetic switches interact in a complex manner, and highlight the promise of combinatorial approaches towards rapidly identifying optimal signals for promoting desired stem cell differentiation.
authors.affiliation: Program of Biomechanical Engineering, Stanford University, Stanford, California 94305, USA.
authors.forename: Anusuya
authors.initials: A
authors.lastname: Ramasubramanian
authors.forename: Stacey
authors.initials: S
authors.lastname: Shiigi
authors.forename: Gordon K
authors.initials: GK
authors.lastname: Lee
authors.forename: Fan
authors.initials: F
authors.lastname: Yang
mesh_terms: D017667:Adipocytes / Q000166:cytology*; D001672:Biocompatible Materials / Q000008:administration & dosage; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression; D018014:Gene Transfer Techniques; D005819:Genetic Markers / Q000235:genetics; D006801:Humans; D010012:Osteogenesis / Q000235:genetics*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology*; D015854:Up-Regulation
chemical_list: C525718:BMP2 protein, human; D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D005819:Genetic Markers; D034741:RNA, Small Interfering