title: Isolation and differentiation of chondrocytic cells derived from human embryonic stem cells using dlk1/FA1 as a novel surface marker.
abstract: Few surface markers are available to monitor lineage differentiation during chondrogenesis. Recently, delta-like1/fetal antigen1 (dlk1/FA1), a transmembrane protein of the Notch/Delta/Serrata family, was shown to be essential for inducing early chondrogenesis. Thus, we investigated the possible use of dlk1/FA1 as a novel surface marker for chondroprogenitor cells during hESC differentiation. We found that, Dlk1/FA1 is expressed specifically in cells undergoing transition from proliferating to prehypertrophic chondrocytes during endochondral ossification of the mouse limb. In hESC cells, dlk1/FA1 was not expressed by undifferentiated hESC, but expressed during in vitro embryoid bodies (hEBs) formation upon down-regulation of undifferentiated markers e.g. Oct 3/4. Similarly, dlk1/FA1 was expressed in chondrocytic cells during in vivo teratoma formation. Interestingly, treatment of hEBs with Activin B, a member of TGF-ss family, markedly increased Dlk1 expression in association with up-regulation of the mesoderm-specific markers (e.g. FOXF1, KDR and VE-cadherin) and SOX9. dlk1/FA1(+) cells isolated by fluorescence activated cell sorting (FACS) were capable of differentiating into chondrocytic cells when cultured as micromass pellets in a xeno-free system containing TGFbeta1. In conclusion, we identified dlk1/FA1 as a novel marker of chondroprogenitor cells that undergo embryonic lineage progression from proliferation to the prehypertrophic stage. Tracking dlk1/FA1 expression as a mesoderm/chondroprogenitor surface marker provides a novel strategy for designing clinically relevant protocols to direct the differentiation of hESC into chondrocytes.
authors.affiliation: Molecular Endocrinology laboratory (KMEB), Medical Biotechnology Centre, Odense University Hospital, University of South Denmark, DK-5000 Odense C, Denmark.
authors.forename: Linda
authors.initials: L
authors.lastname: Harkness
authors.forename: Hanna
authors.initials: H
authors.lastname: Taipaleenmaki
authors.forename: Amer
authors.initials: A
authors.lastname: Mahmood
authors.forename: Ulrik
authors.initials: U
authors.lastname: Frandsen
authors.forename: Anna-Marja
authors.initials: AM
authors.lastname: Saamanen
authors.forename: Moustapha
authors.initials: M
authors.lastname: Kassem
authors.forename: Basem M
authors.initials: BM
authors.lastname: Abdallah
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002356:Cartilage / Q000378:metabolism; D002454:Cell Differentiation; D002460:Cell Line; D019070:Cell Lineage; D002469:Cell Separation; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000166:cytology / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice
chemical_list: D015415:Biomarkers; D002135:Calcium-Binding Proteins; C512941:DLK1 protein, human; C512925:Dlk1 protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D008565:Membrane Proteins