Specification of chondrocytes and cartilage tissues from embryonic stem cells

Abstract

SUMMARYOsteoarthritis 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.

Fate of growth plate hypertrophic chondrocytes: Death or lineage extension?

“…Furthermore, endochondral ossification may encourage better vascularization and allow better integration of graft cartilage with host tissue, improving patient outcomes in musculoskeletal diseases and injuries. Osteogenic differentiation of chondrocytes in culture is well documented (Descalzi Cancedda et al 1992;Gentili et al 1993), so directing stem cells towards a HC phenotype (instead of articular chondrocytes, which do not normally hypertrophy) (Craft et al 2013), might enable generation of cartilage in vitro for grafting and promotion of bone regeneration in patients.…”

Small molecule-directed specification of sclerotome-like chondroprogenitors and induction of a somitic chondrogenesis program from embryonic stem cells

“…Furthermore, the wealth of information emanating from developmental biology studies is expected to aid in the discovery and refinement of such conditions. However, although ESCs have been shown to generate mesenchymal progeny capable of developing cartilage in vitro (Nakayama and Umeda, 2011), the resultant chondrogenic activities were generally poor, and with the exception of ours and a few others (Craft et al, 2013;Oldershaw et al, 2010;Tanaka et al, 2009;Umeda et al, 2012), most reports did not define the developmental origin of the mesenchymal cells generated. The osteochondro-progenitors that develop during embryogenesis are limb bud mesenchyme (derived from lateral plate mesoderm) responsible for limb bone and cartilage generation, sclerotome (from somite/rostral paraxial mesoderm) responsible for rib, vertebral joint, intervertebral disc and vertebral body formation, and ectomesenchyme (from cranial neural crest) responsible for craniofacial bone and cartilage generation.…”

“…The specification process is strictly dependent on the activation of Wnt signaling and suppression of BMP signaling (Craft et al, 2013;Tanaka et al, 2009;Umeda et al, 2012).…”

Induced Pluripotent and Mesenchymal Stem Cells as a Promising Tool for Articular Cartilage Regeneration

“…Craft et al [58] demonstrated that the manipulation of appropriate signal pathways of mouse ESCs, allows obtaining both hypertrophic and non-hypertrophic chondrocyte populations. In this experiment chondrocyte populations were able to form cartilage-like tissue in vitro and support cartilage tissue phenotype within niche of immunodeficient recipients in vivo.…”