Serum from patients with ankylosing spondylitis can increase PPARD, fra-1, MMP7, OPG and RANKL expression in MG63 cells

OBJECTIVES To explore the effects of serum from patients with ankylosing spondylitis on the canonical Wnt/β-catenin pathway and to assess whether the serum has an osteogenic effect in MG63 cells. METHODS MG63 cells were cultured with serum from 45 ankylosing spondylitis patients, 30 healthy controls, or 45 rheumatoid arthritis patients. The relative PPARD, fra-1, MMP7, OPG and RANKL mRNA levels were measured using quantitative real-time polymerase chain reaction. Associations between gene expression and patient demographics and clinical assessments were then analyzed. RESULTS MG63 cells treated with serum from ankylosing spondylitis patients had higher PPARD, fra-1, MMP7 and OPG gene expression than did cells treated with serum from controls or rheumatoid arthritis patients (all p<0.05). RANKL expression was higher in MG63 cells treated with serum from patients with ankylosing spondylitis or rheumatoid arthritis than in those treated with serum from controls (both p<0.05). The OPG/RANKL ratio was also higher in MG63 cells treated with serum from ankylosing spondylitis patients than in those treated with serum from controls (p<0.05). No associations were found between the expression of the five genes and the patient demographics and clinical assessments (all p>0.05). CONCLUSIONS Serum from ankylosing spondylitis patients increases PPARD, fra-1, MMP7, OPG and RANKL expression and the OPG/RANKL ratio in MG63 cells; these effects may be due to the stimulatory effect of the serum on the Wnt pathway.