title: Primary mouse embryonic fibroblasts: a model of mesenchymal cartilage formation.
abstract: Cartilage formation is an intricate process that requires temporal and spatial organization of regulatory factors in order for a mesenchymal progenitor cell to differentiate through the distinct stages of chondrogenesis. Gene function during this process has best been studied by analysis of in vivo cartilage formation in genetically altered mouse models. Mouse embryonic fibroblasts (MEFs) isolated from such mouse models have been widely used for the study of growth control and DNA damage response. Here, we address the potential of MEFs to undergo chondrogenic differentiation. We demonstrate for the first time that MEFs can enter and complete the program of chondrogenic differentiation ex vivo, from undifferentiated progenitor cells to mature, hypertrophic chondrocytes. We show that chondrogenic differentiation can be induced by cell-cell contact or BMP-2 treatment, while in combination, these conditions synergistically enhance chondrocyte differentiation resulting in the formation of 3-dimensional (3-D) cartilaginous tissue ex vivo. Temporal expression profiles of pro-chondrogenic transcription factors Bapx1 and Sox9 and cartilaginous extracellular matrix (ECM) proteins Collagen Type II and X (Coll II and Coll X) demonstrate that the in vivo progression of chondrocyte maturation is recapitulated in the MEF model system. Our findings establish the MEF as a powerful tool for the generation of cartilaginous tissue ex vivo and for the study of gene function during chondrogenesis.
authors.affiliation: Department of Cell Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01655-0106, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Lengner
authors.forename: Christoph
authors.initials: C
authors.lastname: Lepper
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
authors.forename: Janet L
authors.initials: JL
authors.lastname: Stein
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.forename: Jane B
authors.initials: JB
authors.lastname: Lian
mesh_terms: D000469:Alkaline Phosphatase / Q000187:drug effects; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002356:Cartilage / Q000166:cytology / Q000196:embryology* / Q000378:metabolism; D002450:Cell Communication; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D020219:Chondrogenesis; D024043:Collagen Type II / Q000378:metabolism; D024121:Collagen Type X / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology*; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D015870:Gene Expression; D053823:Hedgehog Proteins; D006984:Hypertrophy; D008648:Mesoderm / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D015675:Osteocalcin / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology; D013997:Time Factors; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D016212:Transforming Growth Factor beta
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D024043:Collagen Type II; D024121:Collagen Type X; D053823:Hedgehog Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D016212:Transforming Growth Factor beta; D015675:Osteocalcin; D000469:Alkaline Phosphatase