FGF23 and SOX9 Expression in Haemophilic Cartilage: in Vitro Studies of the Effects of Iron

Introduction Clarifying the links between iron and FGF23, SOX9 expression in chondrocytes would be helpful for comprehending articular cartilage degradation pathogenesis in blood-induced arthritis and exploring new protective methods. Aim The purpose of this study was to determine iron regulation of fibroblast growth factor 23 (FGF23) and SRY-box 9 (SOX9) in human chondrocytes, an area which is unexplored in blood-induced arthritis cartilage degradation pathogenesis. Methods Expression of FGF23, SOX9, MMP13 and collagen II in articular cartilage of patients with osteoarthritis (OA) or haemophilic arthritis (HA) was determined by western blot (WB). Iron induced FGF23 and SOX9 mRNA and protein expression in primary human normal chondrocyte cells (HUM-iCell-s018) was quantifified by qRT-PCR and WB, respectively. Results We found that compared with OA patients, the expression of FGF23, MMP13 in articular cartilage of patients with HA was up-regulated, while the expression of SOX9, collagen II was down-regulated. Iron induced FGF23 and suppressed SOX9 expression in chondrocytes in a dose-dependent manner. Conclusions These findings demonstrated that iron were involved in hemophilic cartilage lesion directly via changing cartilage phenotype through regulation of FGF23 and SOX9 expression in chondrocytes.