Osteogenic differentiation of bone marrow stromal cells induced by coculture with chondrocytes encapsulated in three-dimensional matrices.
Endochondral ossification implicates chondrocyte signaling as an important factor in directing the osteogenic differentiation of mesenchymal stem cells in vivo. In this study, the osteoinductive capabilities of articular chondrocytes suspended in alginate hydrogels were analyzed via coculture with bone marrow stromal cells (BMSCs). In particular, the effect of chondrocyte coculture time on the mechanism underlying this osteogenic induction was examined. Chondrocytes were suspended in alginate beads and cultured above BMSCs in monolayer. Beads containing chondrocytes were removed after 1, 10, or 21 days of coculture. Quantitative reverse transcriptase polymerase chain reaction was used to assess the expression of alkaline phosphatase, bone morphogenetic protein-2, and osteocalcin by BMSCs after days 1, 8, 14, and 21. Calcium deposition was also assayed to characterize the extent of mineralization within cultures. Results indicate that osteogenic differentiation of BMSCs is initiated upon brief exposure to chondrocyte signaling, but requires continued exposure in order to progress fully and maintain an osteoblastic phenotype.
Department of Cell Biology and Genetics, University of Maryland, College Park, Maryland 20742, USA.
Andrew D
AD
Thompson
Martha W
MW
Betz
Diana M
DM
Yoon
John P
JP
Fisher
D000464:Alginates; D000469:Alkaline Phosphatase / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D001672:Biocompatible Materials; D001854:Bone Marrow Cells / Q000166:cytology* / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D018920:Coculture Techniques; D017931:DNA Primers / Q000235:genetics; D020723:Glucuronic Acid; D006603:Hexuronic Acids; D020100:Hydrogels; D015675:Osteocalcin / Q000235:genetics; D010012:Osteogenesis / Q000235:genetics / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017154:Stromal Cells / Q000166:cytology* / Q000378:metabolism; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds
D000464:Alginates; D001672:Biocompatible Materials; C525720:Bmp2 protein, rat; D055396:Bone Morphogenetic Protein 2; D017931:DNA Primers; D006603:Hexuronic Acids; D020100:Hydrogels; D012333:RNA, Messenger; D015675:Osteocalcin; D020723:Glucuronic Acid; D000469:Alkaline Phosphatase; D002118:Calcium