The Role of Transforming Growth Factor β Signaling in Fibroblast‐like Synoviocytes From Patients With Oligoarticular Juvenile Idiopathic Arthritis: Dysregulation of Transforming Growth Factor β Signaling, Including Overexpression of Bone Morphogenetic Protein 4, May Lead to a Chondrocyte Phenotype and May Contribute to Bony Hypertrophy

Dysregulation of the pathways involved in the pathogenesis of oligoarticular JIA were revealed through gene expression profiling. JIA FLS displayed dysregulated TGFβ signaling and exhibited a hypertrophic chondrocyte phenotype. These characteristics, along with contributions from the β-catenin network may have implications for endochondral bone formation and local growth disturbances in oligoarticular JIA. Overexpression of BMP-4 in FLS from patients with oligoarticular JIA in particular may play an important role in disease pathogenesis, with a direct effect on functional outcome and with implications for future treatment.