The JAK inhibitor tofacitinib suppresses synovial JAK1-STAT signalling in rheumatoid arthritis
Ann Rheum Dis. 2014 Nov 14. pii: annrheumdis-2014-206028. doi: 10.1136/annrheumdis-2014-206028. [Epub ahead of print]
Targeting intracellular pathways such as JAK/STAT represents a novel approach to the treatment of RA. Tofacitinib is an oral JAK inhibitor, proven to be effective in the treatment of RA, yet the pathways affected by tofacitinib and the effects on gene expression in situ are unknown. In this study, Boyle et al. tested the hypothesis that tofacitinib targets cytokine signalling critical to the pathogenesis of rheumatoid synovitis by investigating tofacitinib effects on synovial pathobiology.
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An evaluation of risk factors for major adverse cardiovascular events during tocilizumab therapy
Arthritis Rheumatol. 2015;67(2):372–380
The risk of cardiovascular (CV) disease among RA patients, compared with the general population is well documented. Alongside this, studies have been able to establish that risk factors in RA patients are not wholly associated with traditional CV risk factors such as such as diabetes mellitus, hypertension, smoking, and dyslipidemia, suggesting a relationship between parameters of RA disease activity and increased CV risk. Additionally, IL-6 has been linked with the development of coronary heart...
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August 2014
Changes in serum creatinine in patients with active rheumatoid arthritis treated with tofacitinib: results from clinical trials
Arthritis Res Ther. 2014;16(4):R158
Despite preclinical and healthy volunteer studies of tofacitinib showing no evidence of nephrotoxicity, increases in mean serum creatinine levels have been observed in patients treated with the drug during the RA clinical development programme. This report explores the clinical significance of this change.
Serum creatinine values and renal adverse event data were pooled from patients who received =1 dose of tofacitinib either with background DMARDs or as monotherapy in five Phase 3 studie...
Serum creatinine values and renal adverse event data were pooled from patients who received =1 dose of tofacitinib either with background DMARDs or as monotherapy in five Phase 3 studie...
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June 2014
Mechanism of Activation of Protein Kinase JAK2 by the Growth Hormone Receptor
Science 344, 2014; doi: 10.1126/science.1249783
Class I cytokine receptors are key regulators of many processes within the body. The receptors use the JAK-STAT signalling pathway, the deregulation of which causes it to become an important pathway in oncogenesis. Despite this, the processes responsible for JAK2 activation by class I receptors remains elusive. Previous studies using growth hormone and its receptor have led to a model of receptor activation where hormone induced receptor dimerization resulted in close proximity of the receptor i...
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May 2014
JAK2-STAT3 Blockade by AG490 Suppresses Autoimmune Arthritis in Mice via Reciprocal Regulation of Regulatory T cells and Th17 cells
J Immunol 2014; 192:4417-4424
In this study, Park et al sought to investigate the effects of the JAK2 inhibitor, AG490 in RA. Using murine CIA models, both preventative and therapeutic models were investigated. In the preventative model, CIA mice treated with AG490 showed a significantly lower incidence rate of arthritis and arthritic scores when compared to mice injected with vehicle. In the therapeutic model, as in the preventative, AG490 treated mice exhibited less severe arthritis. Through further experiments, it was dem...
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Btk inhibition suppresses agonist-induced human macrophage activation and inflammatory gene expression in RA synovial tissue explants
Ann Rheum Dis Published Online First 24 April 2014 doi:10.1136/annrheumdis-2013-204143
Bruton’s tyrosine kinase, a downstream target of PI3K signalling, has been shown to be crucial in the B lymphocyte and myeloid cell contribution to murine models of arthritis. Synovial tissue samples were taken from biologically naïve RA (n=16) and PsA (n=12) patients in order to assess the expression of BTK. Separate RA synovial explants (n=8) were used to assess the effects of the specific BTK inhibitor RN486. BTK was expressed at equivalent levels in both RA and PsA synovial tissue, however e...
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14-3-3eta is a novel mediator associated with the pathogenesis of rheumatoid arthritis and joint damage
Arthritis Research and Therapy 2014, 16:R99
A major clinical imperative among rheumatologists is the ability to class patients into risk categories for radiographic progression. Indeed, identification of new independent biomarkers predictive of RA disease progression is a key target from OMERACT. This study by Maksymowych et al. sought to clarify the role of 14-3-3? in RA and whether it provided any clinically and/or serologically important prognostic information. First described as being elevated in RA in 2007, 14-3-3? has a strong corre...
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April 2014
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...
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March 2014
Features of the synovium of individuals at risk of developing rheumatoid arthritis
Arthritis and Rheumatology March 2014:66;513-522
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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Inhibition of TAK1 and/or JAK can rescue impaired chondrogenic differentiation of human mesenchymal stem cells in osteoarthritis-like conditions
Tissue Engineering Part A doi:10/1089/ten.TEA.2013.0553
As it is nonvascularized and noninnervated, articular cartilage has a limited capacity to repair which presents a major clinical problem. In order to circumvent this inability to repair, stem cells can be placed into the joint or stimulated within the bone marrow. However, as the cartilage requiring repair is often in diseased joints, the factors involved in the disease state are potentially non-beneficial to the chondrogenesis of mesenchymal stem cells. In this study van Beuningen et al. invest...