Background
Monocytes and macrophages are abundant in rheumatoid synovial tissue and play a major role in the pathogenesis of rheumatoid arthritis (RA) by secreting proinflammatory cytokines such as tumour necrosis factor alpha (TNF-α). An innovative approach is based on the regulation of mRNA stability and degradation, which constitute a critical step in the control of gene expression rather than neutralization of the downstream protein. Stability and degradation of TNF-α mRNA are regulated by cis-acting sequences as AU-rich elements (AREs). Tristetraprolin (TTP), a class of Cys-Cys-Cys-His (CCCH) zinc finger proteins, was identified as the critical TNF-α ARE-binding protein. Importantly, TTP knockout mice develop inflammatory arthritis, dermatitis and myeloid hyperplasia, prevented by anti-TNF-α antibodies. A recent study suggested that a low TTP/TNF-α RNA expression ratio could indicate failure of RA patients to produce adequate amounts of TTP in response to increased TNF-α production. Our aim is to investigate the therapeutic potential of gene expression of ARE-binding elements for anti-TNF-α therapies.