title: [The expression and significance of unfolded protein response-related gene in synovial fluid macrophages in patients with spondyloarthritis and other arthritis].
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.
authors.affiliation: Department of Rheumatology, Chinese PLA General Hospital, Beijing 100853, China. Email: fhuang1964@yahoo.com.
authors.forename: Ling
authors.initials: L
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Zhu
authors.forename: Feng
authors.initials: F
authors.lastname: Huang
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000378:metabolism; D005260:Female; D015870:Gene Expression; D006801:Humans; D007719:Knee Joint; D008264:Macrophages / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000378:metabolism; D010003:Osteoarthritis / Q000378:metabolism; D025241:Spondylarthritis / Q000378:metabolism* / Q000473:pathology; D013582:Synovial Fluid / Q000378:metabolism*; D056811:Unfolded Protein Response / Q000235:genetics*; D055815:Young Adult