Figure 5

FGFR expression profiles and FGFR3 regulation in articular chondrocytes. (A) Age-matched, normal and osteoarthritic human articular chondrocytes in monolayer were subjected to RNA extraction, cDNA synthesis, and qPCR quantification of FGFR3 expression. (B) Age-matched, normal and osteoarthritic human articular chondrocytes were directly lysed for immunoblotting analyses of FGFR3. (C) Age-matched, normal and osteoarthritic chondrocytes were subjected to RNA extraction, cDNA synthesis, and qPCR quantification of FGFR1 and FGFR3 expression. The FGFR1 to FGFR3 expression ratio was calculated in each donor. (D) Human articular chondrocytes in monolayer were pre-incubated with SU5402 (5 μM) or PD98059 (ERK inhibitor, 50 μM) for 1 hour, and then treated with FGF-2 (100 ng/mL) for 24 hours. In parallel, chondrocytes were transfected with siRNA targeting FGFR1 or FGFR3, and then stimulated by FGF-2 (100 ng/mL) for 24 hours. Total RNA was extracted afterwards for cDNA synthesis and qPCR analyses of FGFR3 expression. * P < 0.05. (E) Human articular chondrocytes in monolayer were administered with BMP7 (100 ng/mL) and cultured for 24 hours. Total RNA was extracted afterwards for cDNA synthesis and qPCR analyses of FGFR1 and FGFR3 expression. ERK, extracellular signal-regulated kinase; FGF, fibroblast growth factor; FGFR, FGF receptor; qPCR, quantative polymerase chain reaction.