DNA methylation regulates the expression of CXCL12 in rheumatoid arthritis synovial fibroblasts

Genes Immun. 2011 Dec;12(8):643-52. doi: 10.1038/gene.2011.45. Epub 2011 Jul 14.


In the search for specific genes regulated by DNA methylation in rheumatoid arthritis (RA), we investigated the expression of CXCL12 in synovial fibroblasts (SFs) and the methylation status of its promoter and determined its contribution to the expression of matrix metalloproteinases (MMPs). DNA was isolated from SFs and methylation was analyzed by bisulfite sequencing and McrBC assay. CXCL12 protein was quantified by enzyme-linked immunosorbent assay before and after treatment with 5-azacytidine. RASFs were transfected with CXCR7-siRNA and stimulated with CXCL12. Expression of MMPs was analyzed by real-time PCR. Basal expression of CXCL12 was higher in RASFs than osteoarthritis (OA) SFs. 5-azacytidine demethylation increased the expression of CXCL12 and reduced the methylation of CpG nucleotides. A lower percentage of CpG methylation was found in the CXCL12 promoter of RASFs compared with OASFs. Overall, we observed a significant correlation in the mRNA expression and the CXCL12 promoter DNA methylation. Stimulation of RASFs with CXCL12 increased the expression of MMPs. CXCR7 but not CXCR4 was expressed and functional in SFs. We show here that RASFs produce more CXCL12 than OASFs due to promoter methylation changes and that stimulation with CXCL12 activates MMPs via CXCR7 in SFs. Thereby we describe an endogenously activated pathway in RASFs, which promotes joint destruction.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Aged, 80 and over
  • Arthritis, Rheumatoid / genetics*
  • Arthritis, Rheumatoid / metabolism
  • Chemokine CXCL12 / genetics*
  • Chemokine CXCL12 / metabolism
  • DNA Methylation*
  • Female
  • Fibroblasts / metabolism*
  • Gene Expression
  • Gene Expression Regulation*
  • Humans
  • Male
  • Middle Aged
  • Osteoarthritis / genetics
  • Osteoarthritis / metabolism
  • Promoter Regions, Genetic
  • RNA Interference
  • Receptors, CXCR / genetics
  • Receptors, CXCR / metabolism
  • Synovial Membrane / metabolism*
  • Up-Regulation


  • ACKR3 protein, human
  • Chemokine CXCL12
  • Receptors, CXCR