Figure 2

Aberrant expression of miRNAs in rheumatoid arthritis synoviocytes. (A) Contrary to peripheral blood mononuclear cells (PBMCs) from systemic lupus erythematosus patients, miR-146a is up-regulated in rheumatoid arthritis (RA) synoviocytes and PBMCs. miR-146a is a known regulator of IRAK1 (IL-1 receptor-associated kinase 1) and TRAF6 (TNF receptor-associated factor 6) mRNA and this may be responsible for the altered regulation of IRAK1 and TRAF6, both of which act through the NF-kB pathway to prolong the production of proinflammatory cytokines and chemokines, including TNF-α and IL-1β [3, 55]. (B) miR-124a is down-regulated in synoviocytes from RA patients. Its target proteins, CDK2 (cyclin-dependent kinase 2) and MCP-1 (monocyte chemoattractant protein 1), are up-regulated and this leads to increased synovial proliferation, angiogenesis and chemotaxis [63].