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Arthritis Research & Therapy

Open Access

Post-transcriptional regulation of proinflammatory cytokines in arthritis using gene delivery of AU-rich element binding factors

  • M Khoury1,
  • F Apparailly1,
  • AR Clark3,
  • P Plence1,
  • D Noel1 and
  • C Jorgensen1, 2
Arthritis Research & Therapy20057(Suppl 1):P71

Received: 11 January 2005

Published: 17 February 2005


Rheumatoid ArthritisTHP1 CellElement Binding FactorRheumatoid Synovial TissueTHP1 Human Monocyte


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.


We used the THP1 human monocyte cell line known for a high lipopolysaccharide (LPS)-induced TNF-α secretion. An expression vector containing TTP gene driven by the CMV promoter was constructed. TTP expression was evaluated by western blot following transfection by electroporation (320 mV). The secretion of TNF-α by THP1 was assessed by ELISA before and after TTP transfection (1 μg/106 cells), following LPS stimulation (50 ng/ml).


A significant decrease in TNF-α expression was observed in the TTP-transfected THP1 cells, compared with a GFP mock control. This suppression increased over time and last at least 48 hours after LPS stimulation (23% at 3 hours and 37% at 24 hours).


These preliminary results support an important role of TTP in regulating TNF-α in monocytes and might be the new target for gene delivery in an anti-TNF-α strategy in RA. In vivo evaluation of this strategy in experimental models of RA will be tested.

Authors’ Affiliations

INSERM U475, Université Montpellier I, Montpellier, France
CHU Lapeyronie, service ImmunoRhumatologie, Montpellier, France
Kennedy Institute of Rheumatology Division, Faculty of Medicine, Imperial College London, UK


© BioMed Central Ltd 2005