title: In vitro chondrogenesis of mesenchymal stem cells in recombinant silk-elastinlike hydrogels.
abstract: OBJECTIVE
  In this study the chondrocytic differentiation and cartilage matrix accumulation of human mesenchymal stem cells (hMSCs) were investigated after encapsulation in a genetically engineered silk-elastinlike protein polymer SELP-47 K as an injectable matrix for delivery of cell-based therapeutics.
  
  
  METHODS
  hMSCs were encapsulated in SELP-47 K and cultured for 4 weeks in chondrogenic medium with or without transforming growth factor-beta3 (TGF). Chondrogenic differentiation was evaluated by histological, RNA and biochemical analyses for the expression of cartilage extracellular matrix components.
  
  
  RESULTS
  Histological and immunohistochemical staining revealed that the cells acquired a rounded morphology and were embedded in significant amounts of chondrogenic extracellular matrix. Reverse transcriptase (RT)-PCR showed an up-regulation in aggrecan, type II and type X collagen and SOX9 in presence of TGF-beta3. By day 28, constructs cultured in the presence of TGF-beta3 exhibited significant increase in sulfated glycosaminoglycan and total collagen content up to 65 and 300%, respectively.
  
  
  CONCLUSIONS
  This study demonstrates that SELP-47 K hydrogel can be used as a scaffold for encapsulation and chondrogenesis of hMSCs. The ability to use recombinant techniques to precisely control SELP structure enables the investigation of injectable protein polymer scaffolds for soft-tissue engineering with varied physicochemical properties.
authors.affiliation: Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Haider
authors.forename: Joseph
authors.initials: J
authors.lastname: Cappello
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Ghandehari
authors.forename: Kam W
authors.initials: KW
authors.lastname: Leong
mesh_terms: D053674:Aggrecans / Q000378:metabolism; D002356:Cartilage / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D048430:Cell Shape; D002470:Cell Survival; D002478:Cells, Cultured; D019902:Chondrocytes / Q000378:metabolism*; D020219:Chondrogenesis / Q000235:genetics; D024043:Collagen Type II / Q000378:metabolism; D024121:Collagen Type X / Q000378:metabolism; D004549:Elastin / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D006025:Glycosaminoglycans / Q000378:metabolism; D006609:High Mobility Group Proteins / Q000378:metabolism; D006801:Humans; D020100:Hydrogels; D019476:Insect Proteins / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055758:SOX9 Transcription Factor; D047011:Silk / Q000737:chemistry / Q000378:metabolism* / Q000633:toxicity; D013997:Time Factors; D054457:Tissue Scaffolds; D014157:Transcription Factors / Q000378:metabolism; D053782:Transforming Growth Factor beta3 / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D053674:Aggrecans; D024043:Collagen Type II; D024121:Collagen Type X; D006025:Glycosaminoglycans; D006609:High Mobility Group Proteins; D020100:Hydrogels; D019476:Insect Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D047011:Silk; D014157:Transcription Factors; D053782:Transforming Growth Factor beta3; D004549:Elastin