The expression and significance of unfolded protein response-related gene in synovial fluid macrophages in patients with spondyloarthritis and other arthritis / 中华内科杂志

ABSTRACT

Objective To investigate whether unfolded protein response (UPR) plays a role in the pathogenesis of spondyloarthritis (SpA),and to assess UPR-related gene expression in SpA and other arthritis patients.Methods Eighteen patients with SpA,12 with rheumatoid arthritis (RA) and 6 with osteoarthritis (OA) were recruited.Macrophages were isolated from synovial fluid samples by immunomagnetic separation.The expression of UPR-regulated genes,including binding immunoglobulin protein (BiP),glucose-regulated protein 94 (GRP94),C/EBP homologous protein (CHOP),growth arrested and DNA damage-inducible 34 (GADD34),X-box binding protein 1 (XBP-1) and endoplasmic reticulum DnaJ homolog 4 (ERdj4),was tested by real time polymerase chain reaction (PCR).Results Compared with macrophages in OA patients,the expression of BiP and GRP94 mRNA [(6.06 ± 2.08) × 10-2 vs (1.11 ±0.72) × 10-2 for BiP mRNA,11.80(7.30-38.40) × 10-3 vs 1.27(1.02-4.18) × 10-3 for GRP94 mRNA,both P values ＜0.01] was significantly increased in macrophages in SpA patients.XBP1 mRNA was up-regulated [(12.70 ± 5.20) × 10-3 vs (4.14 ± 2.56) × 10-3,p ＜ 0.01] in SpA group as well.UPR-regulated gene expression in SpA patients with HLA-B27 positive or HLA-B27 negative was similar.However,none of UPR-regulated genes showed different expression between the SpA group and RA group except for GADD34 mRNA [7.30 (5.56-15.40) × 10-3 vs 21.30 (12.20-27.60) × 10-3,P =0.009].Conclusions Our data suggest that UPR possibly participates in the pathogenesis of SpA,although the relationship between HLA-B27 and UPR still needs further investigation.