Fibroblast Growth Factor 19 Disrupts Cartilage Development Via the FGFR4/β-catenin Axis

Fibroblast growth factor 19 (FGF19) has received increasing attention in metabolic disorders of the skeletal system, but its role in cartilage development is poorly understood. In the present study, we used <i>ex vivo</i> metatarsal organ model for nascent cartilage and an AAV-FGF19 overexpression model for adolescent growth plates to demonstrate the influence of FGF19 on cartilage development. We found that FGF19 could impair chondrocyte maturation at the neonatal stage and decrease growth plate thickness at the adolescent stage. FGF19 reduces chondrogenic differentiation of mesenchymal stem cells and the chondrocyte maturation via downregulation of Wnt/β-catenin signalling. FGF19-mediated chondrocyte maturation and cartilage differentiation require the participation of FGFR4 with the aid of β-klotho (KLB). FGF19 signalling entered the cytoplasm through FGFR4, activated the expression of SFRP1, WIF1 and DKK2, which are antagonists of β-catenin signalling, and hindered chondrocyte proliferation and cartilage growth. This study demonstrates for the first time that FGF19 inhibits cartilage development through the FGFR4/β-catenin axis, providing evidence for the vital role of FGF19 in growth plate chondrogenesis and endochondral ossification.