title: Formation of a chondro-osseous rudiment in micromass cultures of human bone-marrow stromal cells.
abstract: Bone-marrow stromal cells can differentiate into multiple mesenchymal lineages including cartilage and bone. When these cells are seeded in high-density 'pellet culture', they undergo chondrogenesis and form a tissue that is morphologically and biochemically defined as cartilage. Here, we show that dual chondro-osteogenic differentiation can be obtained in the same micromass culture of human bone-marrow stromal cells. Human bone-marrow stromal cells were pellet cultured for 4 weeks in chondro-inductive medium. Cartilage 'beads' resulting from the micromass culture were then subcultured for further 1-3 weeks in osteo-inductive medium. This resulted in the formation of a distinct mineralized bony collar around hyaline cartilage. During the chondrogenesis phase, type I collagen and bone sialoprotein were produced in the outer portion of the cartilage bead, which, upon subsequent exposure to beta-glycerophosphate, mineralized and accumulated extracellular bone sialoprotein and osteocalcin. Our modification of the pellet culture system results in the formation of a chondro-osseous 'organoid' structurally reminiscent of pre-invasion endochondral rudiments, in which a bony collar forms around hyaline cartilage. The transition from a cell culture to an organ culture dimension featured by our system provides a suitable model for the dissection of molecular determinants of endochondral bone formation, which unfolds in a precisely defined spatial and temporal frame
authors.affiliation: Istituto Nazionale per la Ricerca sul Cancro, Genova, Italy.
authors.forename: Anita
authors.initials: A
authors.lastname: Muraglia
authors.forename: Alessandro
authors.initials: A
authors.lastname: Corsi
authors.forename: Mara
authors.initials: M
authors.lastname: Riminucci
authors.forename: Maddalena
authors.initials: M
authors.lastname: Mastrogiacomo
authors.forename: Ranieri
authors.initials: R
authors.lastname: Cancedda
authors.forename: Paolo
authors.initials: P
authors.lastname: Bianco
authors.forename: Rodolfo
authors.initials: R
authors.lastname: Quarto
mesh_terms: D000293:Adolescent; D000328:Adult; D001853:Bone Marrow / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology*; D002356:Cartilage / Q000166:cytology; D002454:Cell Differentiation; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D020219:Chondrogenesis; D024042:Collagen Type I / Q000378:metabolism; D005994:Glycerophosphates / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008854:Microscopy, Electron; D008875:Middle Aged; D015675:Osteocalcin / Q000378:metabolism; D010012:Osteogenesis; D012795:Sialoglycoproteins / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology*; D013997:Time Factors
chemical_list: D024042:Collagen Type I; D005994:Glycerophosphates; D012795:Sialoglycoproteins; D015675:Osteocalcin; C031463:beta-glycerophosphoric acid