Figure 4. FCSCs differentiate into chondrocytes and maintain tissue homeostasis through inhibited Wnt.

(a) qRT-PCR show sclerostin induced aggrecan in FCSCs dose-dependently. Data are mean fold change normalized to GAPDH±s.d.; n=3 independent experiments; two-way ANOVA followed by Tukey's post hoc. (b) FCSCs were transfected with luciferase reporter TopFlash and constitutively active βCatenin^S33y plasmid or control vector. Luciferase activity reported at 72 h. Data are mean±s.d.; n=4 independent experiments; paired Student's t-test. (c) qRT-PCR shows S33y FCSCs have decreased cartilage-related genes and increase in Wnt-related gene. Data are mean normalized to GAPDH±s.d.; n=4 independent experiments; paired Student's t-test. (d) Transplanted FCSCs showed aggrecan (ACAN) and βCatenin, but no SOST expression at 3 weeks. Scale bar, 50 μm. (e) Representative immunocytochemistry staining show decreased intracellular βCatenin in sclerostin treated FCSCs (50 ng ml⁻¹) for 48 h. Scale bar, 50 μm. (f) FCSCs were treated with sclerostin (50 ng ml⁻¹) or vehicle for 48 h and transplanted within collagen sponge in nude mice for 6 weeks. Radiographs, uCT and H&E of transplants showed cartilage was maintained and less bone formed in sclerostin treated FCSCs. White scale bar, 2 mm. Black scale bar, 50 μm. (g) Bone volume/tissue volume (BV/TV), bone volume (BV) and bone density (BD) in transplants seeded with FCSCs treated with sclerostin after 6 weeks. Data are mean±s.d.; n=3 transplants; paired Student's t-test. ANOVA, analysis of variance; H&E, haematoxylin and eosin; qRT-PCR, quantitative real-time PCR.