title: Gene expression analysis of rheumatoid arthritis synovial lining regions by cDNA microarray combined with laser microdissection: up-regulation of inflammation-associated STAT1, IRF1, CXCL9, CXCL10, and CCL5.
abstract: OBJECTIVE
  The main histological change in rheumatoid arthritis (RA) is the villous proliferation of synovial lining cells, an important source of cytokines and chemokines, which are associated with inflammation. The aim of this study was to evaluate gene expression in the microdissected synovial lining cells of RA patients, using those of osteoarthritis (OA) patients as the control.
  
  
  METHODS
  Samples were obtained during total joint replacement from 11 RA and five OA patients. Total RNA from the synovial lining cells was derived from selected specimens by laser microdissection (LMD) for subsequent cDNA microarray analysis. In addition, the expression of significant genes was confirmed immunohistochemically.
  
  
  RESULTS
  The 14 519 genes detected by cDNA microarray were used to compare gene expression levels in synovial lining cells from RA with those from OA patients. Cluster analysis indicated that RA cells, including low- and high-expression subgroups, and OA cells were stored in two main clusters. The molecular activity of RA was statistically consistent with its clinical and histological activity. Expression levels of signal transducer and activator of transcription 1 (STAT1), interferon regulatory factor 1 (IRF1), and the chemokines CXCL9, CXCL10, and CCL5 were statistically significantly higher in the synovium of RA than in that of OA. Immunohistochemically, the lining synovium of RA, but not that of OA, clearly expressed STAT1, IRF1, and chemokines, as was seen in microarray analysis combined with LMD.
  
  
  CONCLUSIONS
  Our findings indicate an important role for lining synovial cells in the inflammatory and proliferative processes of RA. Further understanding of the local signalling in structural components is important in rheumatology.
authors.affiliation: Department of Pathology, School of Medicine, Kurume University, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: F
authors.initials: F
authors.lastname: Arakawa
authors.forename: F
authors.initials: F
authors.lastname: Higuchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ishibashi
authors.forename: M
authors.initials: M
authors.lastname: Goto
authors.forename: Y
authors.initials: Y
authors.lastname: Sugita
authors.forename: Y
authors.initials: Y
authors.lastname: Nomura
authors.forename: D
authors.initials: D
authors.lastname: Niino
authors.forename: K
authors.initials: K
authors.lastname: Shimizu
authors.forename: R
authors.initials: R
authors.lastname: Aoki
authors.forename: K
authors.initials: K
authors.lastname: Hashikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Kimura
authors.forename: K
authors.initials: K
authors.lastname: Yasuda
authors.forename: K
authors.initials: K
authors.lastname: Tashiro
authors.forename: S
authors.initials: S
authors.lastname: Kuhara
authors.forename: K
authors.initials: K
authors.lastname: Nagata
authors.forename: K
authors.initials: K
authors.lastname: Ohshima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000235:genetics*; D016022:Case-Control Studies; D018946:Chemokine CCL5 / Q000235:genetics; D054357:Chemokine CXCL10 / Q000235:genetics; D054370:Chemokine CXCL9 / Q000235:genetics; D018925:Chemokines / Q000235:genetics* / Q000378:metabolism; D016000:Cluster Analysis; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000235:genetics; D050856:Interferon Regulatory Factor-1 / Q000235:genetics*; D008297:Male; D042282:Microdissection; D008875:Middle Aged; D020411:Oligonucleotide Array Sequence Analysis; D010003:Osteoarthritis / Q000235:genetics; D050794:STAT1 Transcription Factor / Q000235:genetics*; D013583:Synovial Membrane / Q000378:metabolism*; D015854:Up-Regulation
chemical_list: C483024:CCL5 protein, human; C114753:CXCL10 protein, human; C080810:CXCL9 protein, human; D018946:Chemokine CCL5; D054357:Chemokine CXCL10; D054370:Chemokine CXCL9; D018925:Chemokines; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human