Expression of Osteoclastogenesis-related Genes in Rheumatoid Arthritis Synovial Macrophages

Objective. To examine the mechanism for the inhibited differentiation of osteoclasts in rheumatoid arthritis synovial CD14+ osteoclast precursors, the different expressions of the osteoclastogenesis-related genes in rheumatoid arthritis (RA) synovial fluid CD14+ osteoclast precursors were compared with those of normal peripheral blood (PB) CD14+ osteoclast precursors. Methods. The expression of osteoclastogenesis-related genes were examined using a gene expression oligonucleotide microarray. To validate the results of the microarray analysis, the mRNA expressions of osteoclastogenesis-related genes were measured by real-time PCR. Results. Comparative analysis of the mRNA profiles showed significantly different expression of osteoclastogenesisrelated genes, such as MafB, Id3 and LILRB4, in the RA synovial CD14+ osteoclast precursors, compared to that of normal PB CD14+ osteoclast precursors. Conclusion. The expression of the osteoclastogenesis-related genes in RA synovial CD14+ osteoclast precursors is different from that of the normal PB CD14+ osteoclast precursors. These results suggest that the different expression of osteoclastogenesis-related genes might be involved in the altered osteoclastogenesis in RA synovial osteoclast precursors.