Hypoxia and STAT3 signalling interactions regulate pro-inflammatory pathways in rheumatoid arthritis

. ARD published online first 13 Feb 2014. Doi: 10.1136/annrheumdis-2013-204105

Hypoxia is a key driving force in joint inflammation, however little is known about the effect it can have on JAK/STAT signalling in rheumatoid arthritis. Due to the development of JAK inhibitors as therapeutics it is important to understand any links there may be. Previous studies have shown that HIF1a, a protein associated with hypoxia, facilitates the binding of STAT3 to haptoglobin promoter in HepG2 human hepatoma cells. HIF1a also requires interaction of Notch signalling pathways with STAT3...

March 2014

This study expands on previous findings that synovial inflammation does not coincide with the appearance of rheumatoid arthritis. This was a markedly larger study compared to previous, with 55 individuals assessed. All 55 subjects were positive for IgM rheumatoid factor and/or anti-citrillinated protein antibody as well as possessing no physical evidence of arthritis. 15 of the individuals tested developed arthritis after a median time of 13 months. In these patients the presence of inflammatory...

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Before the onset of clinically apparent disease, the pathogenesis of RA goes through a number of sequential phases. The presence of autoimmunity through RF and ACPAs can be detected up to 13 years before the onset of clinical synovitis. An important component of the immune system is Treg cells which limit damage caused by excessive immune activity. These cells have been found to be dysfunctional in RA. This study aimed to identify autoreactive T cells to a known RA-associated antigen and determi...

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February 2014

Despite biologic therapies greatly improving the treatment of rheumatoid arthritis, many patients do not respond to current treatments or do not maintain response to these treatments. This review covers the evidence for the newly discovered role of Th17 cells, IL-12 and IL-17 family of cytokines in the pathogenesis of RA as well as the development of new therapies targeting these cytokines. With current biologics targeting cytokines such as TNF, IL-1ß and IL-6, the discovery of the Th17 subset o...

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Systematic literature reviews were undertaken to assess the efficacy of csDMARDs, glucocorticoids and tofacitinib in the treatment of RA. The first two were updates to reviews conducted for the 2010 recommendations while the tofacitinib SLR was a complete review.Two studies identified by the csDMARD SLR, tREACH and TEAR, compared efficacy between MTX mono- and combination therapy (MTX+SSZ+HQ). Both of these studies found there was no benefit to immediate triple therapy.Further studies analysing ...
Two systematic literature reviews were undertaken to update the safety findings on synthetic and biological DMARDs in order to inform the updates to the EULAR recommendations to the treatment of RA. Of 10,559 articles screened, 49 were included for review covering a diverse range of outcomes. In the main these showed the patients on bDMARDs had a significantly greater risk of serious infections and tuberculosis compared with csDMARDs, while differences in data between studies mean a slight incre...

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Due to its function as a JAK1/3 inhibitor, tofacitinib has effects on a wide ranging variety of cells. The authors of this paper have previously reported a suppression in cytokine production by CD4+ T lymphocytes caused by tofacitinib, while others have reported reduced chemokine production from fibroblast-like synoviocytes. The effects of tofacitinib on other cells however remain largely unknown. This study focused on tofacitinib’s effects on CD4+ T lymphocyte proliferation and on subsets of ly...

January 2014

Spleen tyrosine kinase (SYK) has already been described as a potential therapeutic target for the treatment of autoimmune diseases. Previously the SYK inhibitor fostamatinib was in clinical development for the treatment of rheumatoid arthritis, but has since been suspended. However, investigation into SYK inhibition continues with RO2091, a novel ATP-competitive inhibitor of SYK with reasonable selectivity, potency and oral bioavailability which has been shown to suppress various innate and adap...

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A large number of loci implicated in disease susceptibility have been identified through genome-wide association studies (GWAS). In this review article, Diogo et al. discuss recent advances in GWAS in the context of rheumatoid arthritis pathogenesis and clinical applications. Relevant cells types and pathways in RA highlighted by GWAS to date include regulatory T-cells and CD4+ memory T cells as well as the JAK/STAT and NF-kB signalling pathways. The development of drugs targeting these pathways...

Emerging cell and cytokine targets in rheumatoid arthritis

Nat Rev Rheumatol. 2013. doi:10.1038/nrrheum.2013.168

Despite major progress in the treatment of RA over the past decade, sustained clinical remission remains elusive. The identification of new treatment targets is therefore necessary, with much research currently being undertaken in this area. Novel therapeutic approaches currently being investigated include T cell-directed therapies targeting both T cell activation and regulation; and the targeting of pathogenic B cell functions, including the use of depleting and non-depleting B cell-directed an...

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