title: Specification of chondrocytes and cartilage tissues from embryonic stem cells.
abstract: Osteoarthritis primarily affects the articular cartilage of synovial joints. Cell and/or cartilage replacement is a promising therapy, provided there is access to appropriate tissue and sufficient numbers of articular chondrocytes. Embryonic stem cells (ESCs) represent a potentially unlimited source of chondrocytes and tissues as they can generate a broad spectrum of cell types under appropriate conditions in vitro. Here, we demonstrate that mouse ESC-derived chondrogenic mesoderm arises from a Flk-1(-)/Pdgfrα(+) (F(-)P(+)) population that emerges in a defined temporal pattern following the development of an early cardiogenic F(-)P(+) population. Specification of the late-arising F(-)P(+) population with BMP4 generated a highly enriched population of chondrocytes expressing genes associated with growth plate hypertrophic chondrocytes. By contrast, specification with Gdf5, together with inhibition of hedgehog and BMP signaling pathways, generated a population of non-hypertrophic chondrocytes that displayed properties of articular chondrocytes. The two chondrocyte populations retained their hypertrophic and non-hypertrophic properties when induced to generate spatially organized proteoglycan-rich cartilage-like tissue in vitro. Transplantation of either type of chondrocyte, or tissue generated from them, into immunodeficient recipients resulted in the development of cartilage tissue and bone within an 8-week period. Significant ossification was not observed when the tissue was transplanted into osteoblast-depleted mice or into diffusion chambers that prevent vascularization. Thus, through stage-specific manipulation of appropriate signaling pathways it is possible to efficiently and reproducibly derive hypertrophic and non-hypertrophic chondrocyte populations from mouse ESCs that are able to generate distinct cartilage-like tissue in vitro and maintain a cartilage tissue phenotype within an avascular and/or osteoblast-free niche in vivo.
authors.affiliation: McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON, M5G 1L7, Canada.
authors.forename: April M
authors.initials: AM
authors.lastname: Craft
authors.forename: Nazish
authors.initials: N
authors.lastname: Ahmed
authors.forename: Jason S
authors.initials: JS
authors.lastname: Rockel
authors.forename: Gurpreet S
authors.initials: GS
authors.lastname: Baht
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Alman
authors.forename: Rita A
authors.initials: RA
authors.lastname: Kandel
authors.forename: Agamemnon E
authors.initials: AE
authors.lastname: Grigoriadis
authors.forename: Gordon M
authors.initials: GM
authors.lastname: Keller
mesh_terms: D000818:Animals; D055415:Bone Morphogenetic Protein 4 / Q000235:genetics / Q000378:metabolism; D002358:Cartilage, Articular / Q000166:cytology* / Q000378:metabolism; D002454:Cell Differentiation; D019070:Cell Lineage; D019902:Chondrocytes / Q000166:cytology* / Q000378:metabolism; D020219:Chondrogenesis; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000378:metabolism / Q000637:transplantation; D005260:Female; D055428:Growth Differentiation Factor 5 / Q000235:genetics / Q000378:metabolism; D006984:Hypertrophy / Q000378:metabolism; D007150:Immunohistochemistry; D008648:Mesoderm / Q000166:cytology / Q000378:metabolism; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism; D010012:Osteogenesis; D020796:Receptor, Platelet-Derived Growth Factor alpha / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D013997:Time Factors
chemical_list: C525810:Bmp4 protein, mouse; D055415:Bone Morphogenetic Protein 4; C525894:Gdf5 protein, mouse; D055428:Growth Differentiation Factor 5; D020796:Receptor, Platelet-Derived Growth Factor alpha
keywords: Cartilage; Chondrocyte; Embryonic stem cell; Induced pluripotent stem cell; Paraxial; Somite